Document Identifier: DSP0266

Date: 2019-05-16

Version: 1.7.0

Redfish Specification

Information for Work-in-Progress version:

IMPORTANT: This document is not a standard. It does not necessarily reflect the views of the DMTF or its members. Because this document is a Work in Progress, this document may still change, perhaps profoundly and without notice. This document is available for public review and comment until superseded.

Provide any comments through the DMTF Feedback Portal: http://www.dmtf.org/standards/feedback

Supersedes: 1.6.1

Document Class: Normative

Document Status: Published

Document Language: en-US

Document Confidentiality:

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This document's normative language is English. Translation into other languages is permitted.

CONTENTS

Foreword

The Redfish Forum of the DMTF develops the Redfish standard.

DMTF is a not-for-profit association of industry members that promotes enterprise and systems management and interoperability. For information about the DMTF, see https://www.dmtf.org/.

Acknowledgments

The DMTF acknowledges the following individuals for their contributions to the Redfish standard, including this document and Redfish Schemas, interoperability profiles, and message registries:

1. Abstract

Redfish is a standard that uses RESTful interface semantics to access a schema based data model to conduct management operations. It is suitable for a wide range of devices, from stand-alone servers, to composable infrastructures, and to large-scale cloud environments.

The initial Redfish scope targeted servers.

The DMTF and its alliance partners expanded that scope to cover most data center IT equipment and other solutions, and both in- and out-of-band access methods.

Additionally, the DMTF and other organizations that use Redfish as part of their industry standard or solution have added educational material.

2. Normative references

The following referenced documents are indispensable for the application of this document. For dated or versioned references, only the edition cited (including any corrigenda or DMTF update versions) applies. For references without a date or version, the latest published edition of the referenced document (including any corrigenda or DMTF update versions) applies.

3. Terms and definitions

Some terms and phrases in this document have specific meanings beyond their typical English meanings. This clause defines those terms and phrases.

The terms "shall" ("required"), "shall not", "should" ("recommended"), "should not" ("not recommended"), "may", "need not" ("not required"), "can" and "cannot" in this document are to be interpreted as described in ISO/IEC Directives, Part 2, Clause 7. The terms in parenthesis are alternatives for the preceding term, for use in exceptional cases when the preceding term cannot be used for linguistic reasons. Note that ISO/IEC Directives, Part 2, Clause 7 specifies additional alternatives. Occurrences of such additional alternatives shall be interpreted in their normal English meaning.

The terms "clause", "subclause", "paragraph", and "annex" in this document are to be interpreted as described in ISO/IEC Directives, Part 2, Clause 6.

The terms "normative" and "informative" in this document are to be interpreted as described in ISO/IEC Directives, Part 2, Clause 3. In this document, clauses, subclauses, or annexes labeled "(informative)" do not contain normative content. Notes and examples are always informative elements.

This document defines these additional terms:

Term Definition
Baseboard management controller (BMC) Embedded device or service. Typically an independent microprocessor or system-on-chip with associated firmware in a computer system that completes out-of-band systems monitoring and management-related tasks.
Collection See Resource Collection.
CRUD Basic Create, Read, Update, and Delete operations that any interface can support.
Event Data structure that corresponds to one or more alerts.
Hypermedia API API that you navigate through URIs that a service returns.
Managed system System that provides information, status, or control via a Redfish-defined interface.
Member Single resource instance in a Resource Collection.
Message Complete HTTP- or HTTPS-formatted request or response. In the REST-based Redfish protocol, every request should result in a response.
OData Open Data Protocol, as defined in OData-Protocol.
OData service document Resource that provides information about the service root for generic OData clients.
Operation The HTTP request methods that map generic CRUD operations. These are POST, GET, PUT/PATCH, HEAD and DELETE.
Property Name-and-value pair in a Redfish-defined request or response. A property can be any valid JSON data type.
Redfish client Communicates with a Redfish Service and accesses one or more of the service's resources or functions.
Redfish event receiver Software that runs at the event destination that receives events from a Redfish Service.
Redfish protocol Discovers, connects to, and inter-communicates with a Redfish Service.
Redfish Schema Defines Redfish Resources according to OData schema representation. You can directly translate a Redfish Schema to a JSON Schema representation.
Redfish Service Implementation of the protocols, resources, and functions that deliver the interface that this specification defines and its associated behaviors for one or more managed systems. Also known as the service.
Redfish Provider A Redfish provider interacts with the Redfish Service to contribute resources to the Redfish Resource tree and reacts to changes in its owned resources. There are two types of Redfish providers: internal providers and external providers. A internal provider is the Redfish Service itself that has a data model and can react to RESTful operations from a client. An external provider is a designed means for agents external to the Redfish Service to augment the Redfish Resource tree. The interaction between a Redfish provider and a Redfish Service is not covered by this specification.
Request Message from a client to a service.
Resource Addressable by a URI and represents a Redfish data structure.
Resource Collection Resource that contains a set of like resources where the number of instances can shrink or grow.
Resource tree Tree structure of resources accessible through a well-known starting URI. A client may discover the resources available on a Redfish Service by following the resource hyperlinks from the base of the tree.
Response Message from a service to a client in response to a request message.
Service root Resource that serves as the starting point for locating and accessing the other resources and associated metadata that together make up an instance of a Redfish Service.
Subscription Registration of a destination to receive events.

4. Acronyms

This document uses these acronyms:

Acronym Definition
BMC Baseboard management controller
CRUD Create, Replace, Update and Delete
CSRF Cross-Site Request Forgery
HTTP Hypertext Transfer Protocol
HTTPS Hypertext Transfer Protocol over TLS
IP Internet Protocol
IPMI Intelligent Platform Management Interface
JSON JavaScript Object Notation
KVM-IP Keyboard, Video, Mouse redirection over IP
NIC Network Interface Card
PCI Peripheral Component Interconnect
PCIe PCI Express
TCP Transmission Control Protocol
XSS Cross-Site Scripting

5. Overview

Redfish is a management standard that uses a data model representation with a RESTful interface.

Being RESTful, Redfish is easier to use and implement.

Being model-oriented, it can express the relationships between components and the semantics of the services and components within them. The model is also easy to extend.

By requiring JSON representation, Redfish enables easy integration with programming environments. It is also easy to interpret by humans.

The model is defined by an interoperable Redfish Schema. It is published in OpenAPI YAML, OData CSDL, and JSON Schema, and is freely available.

5.1. Scope

This specification defines the required protocols, data model, behaviors, and other architectural components for an interoperable, multivendor, remote, and out-of-band capable interface. This interface meets the cloud-based and web-based IT professionals' expectations for scalable platform management. While large and hyperscale environments are the primary focus, clients can use the specification for individual system management.

The specifications defines elements that are mandatory for all Redfish implementations, as well as optional elements that can be chosen by system vendors or manufacturers. This specification also defines points at which extensions specific to the OEM (system vendor) can be provided by a given implementation.

The specification sets normative requirements for Redfish Services and associated materials, such as Redfish Schema files. In general, the specification does not set requirements for Redfish clients, but indicates what a Redfish client should do to successfully and effectively access and use a Redfish Service.

The specifications do not require that implementation of the Redfish interfaces and functions require particular hardware or firmware.

5.2. Goals

As an architecture, data representation, and definition of protocols that enable a client to access Redfish Services, Redfish has these goals:

Goal Purpose
Scalable Stand-alone machines and racks of equipment.
Flexible Can be implemented with existing hardware, or entirely as a software service.
Extensible New and vendor-specific capabilities can be easily added to the data model.
Backward-compatible Additional capabilities can be added while preserving investments in implementations of earlier versions of the specification.
Interoperable Consistent functionality across multiple vendor implementations.
Standards-based Built on ubiquitous and secure protocols and leveraging other standards where applicable.
Simple Usable without the need for highly specialized programming skills or systems knowledge.
Lightweight Designed to reduce complexity and implementation cost, as well as minimizing required footprint for implementations.

5.3. Design tenets

To deliver these goals, Redfish adheres to these design tenets:

5.4. Limitations

Redfish minimizes the need for clients to complete upgrades by using strict versioning and forward-compatibility rules, and separation of the protocols from the data model. However, Redfish does not guarantee that clients never need to update their software. For example, clients might need to upgrade for managing new types of systems or components, as well as updates to the data model.

Interoperable does not mean identical. Many elements of Redfish are optional. Clients should be prepared to discover the optional elements using the built in discovery methods.

The resource tree reflects the topology of the system and its devices. Consequently, different hardware or device types result in different resource trees, even for identical systems from the same manufacturer. References between resources may result in a graph instead of a tree. Clients that traverse the resource tree should provide logic to avoid infinite loops.

Additionally, not all Redfish Resources use simple REST read-and-write semantics. Different use cases may follow other types of client logic. For example, clients cannot simply read user credentials or certificates from one service and write them to another service.

Finally, the hyperlink values between resources and other elements can vary across implementations. Clients should not assume that they can reuse hyperlinks across different Redfish Service instances.

5.5. Additional design background and rationale

5.5.1. REST-based

Redfish exposes many service applications as RESTful interfaces. This document defines a RESTful interface.

Redfish defines a RESTful interface because it:

5.5.2. Data oriented

The Redfish data model is developed by focusing on the contents of the payload. By concentrating on the contents of the payload first, Redfish payloads are easily mapped to schema definition languages and encoding types. The data model is defined in various schema languages, including OpenAPI YAML, OData CSDL, and JSON Schema.

5.5.3. Separation of protocol from data model

Redfish separates the protocol operations from the data model and versions the protocol independently from the data model. This enables clients to extend and change the data model as needed without requiring the protocol version to change.

5.5.4. Hypermedia API service root

Redfish has a single service root URI and clients can discover all other resources through referenced URIs.

5.5.5. OpenAPI v3.0 support

The OpenAPI Specification v3.0 provides a rich ecosystem of tools for using RESTful interfaces that meet the design requirements of that specification. Starting with v1.6.0 of the Redfish Specification, the Redfish Schemas support the OpenAPI YAML file format, and URI patterns that conform to the OpenAPI Specification were defined. Conforming Redfish Services that support the Redfish protocol version v1.6.0 or later implement those URI patterns to enable use of the OpenAPI ecosystem.

5.5.6. Follow OData conventions

With the popularity of RESTful APIs, there are nearly as many RESTful interfaces as there are applications. While following REST patterns helps promote good practices, due to design differences between the many RESTful APIs there few common conventions between them.

To provide for interoperability between APIs, OData defines a set of common RESTful conventions and annotations. Redfish adopts OData conventions for describing schema, URL conventions, and definitions for typical properties in a JSON payload.

5.6. Service elements

5.6.1. Synchronous and asynchronous operation support

Some operations can take more time than a client typically wants to wait. For this reason, some operations can be asynchronous at the discretion of the service. The request portion of an asynchronous operation is no different from the request portion of a synchronous operation.

To determine whether an operation was completed synchronously or asynchronously, clients can review the HTTP status codes. For more information, see the Asynchronous operations clause.

5.6.2. Eventing mechanism

Redfish provides the ability to send messages outside the normal request and response paradigm to clients. The service uses these messages, or events, to asynchronously notify the client of a state change or error condition, usually of a time critical nature.

Two styles of eventing are currently defined by this specification - push style eventing, and Server-Sent Events (SSE).

In push style eventing, when the service detects the need to send an event, it uses an HTTP POST to push the event message to the client. Clients can enable reception of events by creating a subscription entry in the Event Service, or an administrator can create subscriptions as part of the Redfish Service configuration.

In SSE style eventing, the client opens an SSE connection to the service by performing a GET on the URI specified by the "ServerSentEventUri" in the Event Service.

For information, see the Eventing clause.

5.6.3. Actions

Actions are Redfish operations that do not easily map to RESTful interface semantics. These types of operations may not directly affect properties in the Redfish Resources. The Redfish Schema defines certain standard actions for common Redfish Resources. For these standard actions, the Redfish Schema contains the normative language on the behavior of the action.

5.6.4. Service discovery

While the service itself is at a well-known URI, clients need to discover the network address of the service. Like UPnP, Redfish uses SSDP for discovery. A wide variety of devices, such as printers and client operating systems, support SSDP. It is simple, lightweight, IPv6 capable, and suitable for implementation in embedded environments.

For more information, see the Discovery clause.

5.6.5. Remote access support

Remote management functionality typically includes access mechanisms for redirecting operator interfaces such as serial console, keyboard video and mouse (KVM-IP), command shell (i.e., command line interface), and virtual media. While these mechanisms are critical functionality, they cannot be reasonably implemented as a RESTful interface. Therefore, this standard does not define the protocols or access mechanisms for those services, but encourages implementations that leverage existing standards. However, the Redfish schema includes resources and properties allowing client discovery of these capabilities and describing access mechanisms to enable interoperability.

5.7. Security

The challenge of remote interface security is to protect both the interface and exchanged data. To accomplish this, Redfish provides authentication and encryption. As part of this security, Redfish defines and requires minimum levels of encryption.

For more information, see the Security details clause.

6. Protocol details

In this document, the Redfish protocol refers to the RESTful mapping to HTTP, TCP/IP and other protocol, transport, and messaging layer aspects. HTTP is the application protocol that will be used to transport the messages and TCP/IP is the transport protocol. The RESTful interface is a mapping to the message protocol.

The Redfish protocol is designed around a web service based interface model. This provides network and interaction efficiency for both user interface (UI) and automation usage. Specifically, the ability to leverage existing tool chains.

The Redfish protocol uses:

A Redfish interface shall be exposed through a web service endpoint implemented using HTTP, version 1.1 (RFC7230, RFC7231, RFC7232).

The subsequent clauses describe how the Redfish interface uses and adds constraints to HTTP to ensure interoperability of Redfish implementations.

6.1. Universal Resource Identifiers

A Universal Resource Identifier (URI) identifies a resource, including the service root and all Redfish Resources.

Performing a GET operation on a URI yields a representation of the resource containing properties and hyperlinks to associated resources. The service root URI is well known and is based on the protocol version. Discovering the URIs to additional resources is done through observing the associated resource hyperlinks returned in previous responses. This practice, known as hypermedia, allows for the discovery of resources by following hyperlinks.

Redfish considers the RFC3986-defined scheme, authority, root service and version, and unique resource path component parts of the URI.

For example, the https://mgmt.vendor.com/redfish/v1/Systems/1 URI contains these component parts:

Component part In the example
The scheme. https:
The authority, which defines the authority to which to delegate the URI. //mgmt.vendor.com
The root service and version. /redfish/v1/
The resource path, which provides a unique identifier for the resource. Systems/1

In a URI:

In an implementation:

For the absolute URI definition, see RFC3986.

For example, a POST operation may return the /redfish/v1/Systems/2 URI in the Location header of the response, which points to the POST-created resource.

Assuming that the client connects through the mgmt.vendor.com appliance, the client accesses the resource through the https://mgmt.vendor.com/redfish/v1/Systems/2 absolute URI.

RFC3986-compliant URIs may also contain the query, ?query, and frag, #frag, components. For information about queries, see Query parameters. When a URI includes a fragment (frag) to submit an operation, the server ignores the fragment.

If a property in a response is a reference to another property within a resource, use the RFC6901-defined URI Fragment Identifier Representation format. If the property is as a reference property in the schema, the fragment shall reference a valid Resource identifier. For example, the following fragment identifies a property at index 0 of the Fans array in the /redfish/v1/Chassis/MultiBladeEncl/Thermal resource:

{
    "@odata.id": "/redfish/v1/Chassis/MultiBladeEncl/Thermal#/Fans/0"
}

6.2. HTTP methods

The following table describes the mapping of HTTP methods to the operations that are supported by Redfish. The "required" column specifies whether the method is supported by a Redfish interface.

For HTTP methods not supported by the Redfish Service or not listed in the table, an HTTP 405 status code shall be returned by the Redfish Service.

HTTP method Interface semantic Required
POST Object create
Object action
Eventing		 Yes
GET Object retrieval Yes
PUT Object replace No
PATCH Object update Yes
DELETE Object delete Yes
HEAD Object header retrieval No
OPTIONS Header retrieval
Cross-Origin Resource Sharing (CORs) preflight		 No

6.3. HTTP redirect

HTTP redirect enables a service to redirect a request to another URL. Among other things, HTTP redirect enables Redfish Resources to alias areas of the data model.

NOTE: Refer to the Security details clause for security implications of HTTP Redirect.

6.4. Media types

Some resources may be available in more than one type of representation. The media type indicates the representation type.

In HTTP messages, the media type is specified in the Content-Type header. To tell a service to send the response through certain media types, the client sets the HTTP Accept header to a list of the media types.

To request compression, clients specify an Accept-Encoding request header.

When requested by the client, services should support gzip compression.

6.5. ETags

To reduce unnecessary RESTful accesses to resources, the Redfish Service should support the association of a separate entity tag (ETag) with each resource.

Because the service knows whether the new version of the object is substantially different, the service generates and provides the ETag as part of the resource payload.

The ETag mechanism supports both strong and weak validation. If a resource supports an ETag, it shall use the RFC7232-defined ETag strong validator.

This specification does not mandate a particular algorithm for ETag creation, but ETags should be highly collision-free.

An ETag can be:

If a client calls PUT or PATCH to update a resource, it should include an ETag from a previous GET in the HTTP If-Match or If-None-Match header. If a service supports the return of the ETag header on a resource, the service may respond with HTTP 428 status code if the If-Match or If-None-Match header is missing from the PUT or PATCH request for the same resource, as specified in RFC6585.

In addition to the return of the ETag property on each resource, a Redfish Service should return the ETag header on:

The format of the ETag header is:

ETag: "<string>"

6.6. Protocol version

The protocol version is separate from the resources' version or the Redfish Schema version that the resources support.

Each Redfish protocol version is strongly typed by using the URI of the Redfish Service in combination with the resource obtained at that URI, called the ServiceRoot resource.

The root URI for this version of the Redfish protocol shall be /redfish/v1/.

The URI defines the major version of the protocol.

The RedfishVersion property of the ServiceRoot resource defines the protocol version, which includes the major version, minor version, and errata version of the protocol, as defined in the Redfish Schema for that resource.

The protocol version is a string in the format:

MajorVersion.MinorVersion.ErrataVersion

where

Variable Type Version Description
MajorVersion Integer Major A backward-compatible class change.
MinorVersion Integer Minor A minor update. Redfish introduces new functionality but does not remove any functionality.
The minor version preserves compatibility with earlier minor versions.
ErrataVersion Integer Errata A fix in the earlier version.

Any resource that a client discovers through hyperlinks that the root service or any root service-referenced service or resource returns shall conform to the same protocol version that the root service supports.

A GET operation on the /redfish resource shall return this response body:

{
    "v1": "/redfish/v1/"
}

6.7. Redfish-defined URIs and relative reference rules

A Redfish Service shall support these Redfish-defined URIs:

URI Returns
/redfish The version. A major update that does not preserve compatibility with earlier minor versions.
/redfish/v1/ The Redfish service root.
/redfish/v1/odata The Redfish OData service document.
/redfish/v1/$metadata The Redfish metadata document.

In addition, the service shall process the following URI without a trailing slash in one of these ways:

URI Associated Redfish-defined URI
/redfish/v1 /redfish/v1/

All other Redfish Service-supported URIs shall match the Resource URI patterns definitions, except the supplemental resources that the @Redfish.Settings, @Redfish.ActionInfo, and @Redfish.CollectionCapabilities payload annotations reference. The client shall treat the URIs for these supplemental resources as opaque.

All Redfish Service-supported URIs are reserved for future standardization by DMTF and DMTF alliance partners, except OEM extension URIs, which shall conform to the OEM resource URI requirements.

All relative references (see RFC3986) that the service uses shall start with either:

7. Service requests

This clause describes the requests that clients can send to Redfish Services.

7.1. Request headers

The HTTP specification defines headers that can be used in request messages. The following table defines those headers and their requirements for Redfish Services and Clients.

For Redfish Services:

For Redfish Clients (sending the HTTP requests):

Header Service requirement Client requirement Supported values Description
Accept Yes No RFC7231

Communicates to the server the media type or types that this client is prepared to accept.

Services shall support Resource requests with Accept header values of application/json or application/json;charset=utf-8

Services shall support metadata requests with Accept header values of application/xml or application/xml;charset=utf-8

Services shall support any request with Accept header values of application/*, application/*;charset=utf-8, */*, or */*;charset=utf-8
Accept-Encoding No No RFC7231

Indicates whether the client can handle gzip-encoded responses.

If a service cannot send an acceptable response to a request with this header, it shall respond with the HTTP 406 status code.

If the request omits this header, the service shall not return gzip-encoded responses.
Accept-Language No No RFC7231

The languages that the client accepts in the response.

If the request omits this header, uses the service's default language for the response.
Authorization Conditional Conditional RFC7235, Section 4.2

Required for Basic authentication.

A client can access unsecured resources without this header on systems that support basic authentication.
Content-Length No No RFC7231

The size of the message body.

To indicate the size of the body, a client can use the Transfer-Encoding: chunked header.

If a service must use Content-Length and does not support Transfer-Encoding, it responds with the HTTP 406 status code.
Content-Type Conditional Conditional RFC7231

The request format. Required for operations with a request body.

Services shall accept the Content-Type header set to either application/json or application/json;charset=utf-8.

It is recommended that clients use these values in requests because other values can cause an error.
Host Yes No RFC7230

Enables support of multiple origin hosts at a single IP address.
If-Match Conditional No RFC7232

To ensure that clients update the resource from a known state, PUT and PATCH requests for resources for which a service returns ETags shall support If-Match.

While not required for clients, it is highly recommended for PUT and PATCH operations.
If-None-Match No No RFC7232

A service only returns the resource if the current ETag of that resource does not match the ETag sent in this header.

If the ETag in this header matches the resource's current ETag, the GET operation returns the HTTP 304 status code.
Last-Event-ID No No HTML5 SSE

The event source's last event ID. Requests history event data.

See Server-Sent Events.
Max-Forwards No No RFC7231

Limits gateway and proxy hops.

Prevents messages from remaining in the network indefinitely.
OData-MaxVersion No No 4.0

The maximum OData version that an OData-aware client understands.
OData-Version Yes No 4.0

The OData version.

Services shall reject requests that specify an unsupported OData version.

If a service encounters an unsupported OData version, it should reject the request with the HTTP 412 status code.
Origin Yes No W3C CORS, Section 5.7

Enables web applications to consume a Redfish Service while preventing CSRF attacks.
User-Agent Yes No RFC7231

Traces product tokens and their versions.

The header can list multiple product tokens.
Via No No RFC7230

Defines the network hierarchy and recognizes message loops.

Each pass inserts its own Via header.

Redfish Services shall understand and be able to process the headers in the following table as defined by this specification if the value in the Required column is Yes.

Header Service requirement Client requirement Supported values Description
X-Auth-Token Yes Conditional Opaque encoded octet strings Authenticates user sessions.
The token value shall be indistinguishable from random.
While services shall support this header, a client can access unsecured resources without establishing a session.

7.2. GET (read requests)

The GET operation is used to retrieve resources from a Redfish Service. Clients make a GET request to the individual resource URI. Clients may obtain the resource URI from published sources, such as the OpenAPI document, or from a Resource identifier property in a previously retrieved resource response, such as the Links Property.

The service shall return the resource representation using one of the media types listed in the Accept header, subject to the media types' requirements. If the Accept header is absent, the service shall return the resource's representation as application/json. Services may, but are not required to, support the convention of retrieving individual properties within a resource by appending a segment containing the property name to the URI of the resource.

7.2.1. Resource Collection requests

Clients retrieve a Resource Collection by making a GET request to the Resource Collection URI. The response includes the Resource Collection's properties and an array of its Members.

No requirements are placed on implementations to return a consistent set of members when a series of requests that use paging query parameters are made over time to obtain the entire set of members. It is possible that these calls can result in missed or duplicate elements if multiple GETs are used to retrieve the Members array instances through paging.

A subset of the members can be retrieved using client paging query parameters.

A service may not be able to return all of the contents of a Resource Collection request in a single response body. In this case, the response can be paged by the service. If a service pages a response to a Resource Collection request, the following rules shall apply:

7.2.2. Service root request

The root URL for Redfish version 1.x services shall be /redfish/v1/.

The service returns the ServiceRoot resource, as defined by this specification, as a response for the root URL.

Services shall not require authentication to retrieve the service root and /redfish resources.

7.2.3. OData service and $metadata document requests

Redfish Services expose two OData-defined documents at specific URIs to enable generic OData clients to navigate the Redfish Service.

7.3. Query parameters

To paginate, retrieve subsets of resources, or expand the results in a single response, clients can include the query parameters. Some query parameters apply only to Resource Collections.

Services:

Service shall return:

The response body shall reflect the evaluation of the query parameters in this order:

Query parameter Description and example
excerpt

Returns a subset of the resource's properties that match the defined Excerpt schema annotation.

If no Excerpt schema annotation is defined for the resource, the entire resource is returned.

Example:

http://resource?excerpt
$expand=<string>

Returns a hyperlink and its contents in-line with retrieved resources, as if a GET call response was included in-line with that hyperlink.

See Use of the $expand query parameter.

Example:

http://resource?$expand=*($levels=3)

http://resourcecollection?$expand=.($levels=1)
$filter=<string>

Applies to Resource Collections. Returns a subset of collection members that match the $filter expression.

See Use of the $filter query parameter.

Example:

http://resourcecollection?$filter=SystemType eq 'Physical'
only

Applies to Resource Collections. If the target Resource Collection contains exactly one member, clients can use this query parameter to return that member's resource.

If the collection contains either zero members or more than one member, the response returns the collection resource, as expected.

Example:

http://resourcecollection?only
$select=<string>

Returns a subset of the resource's properties that match the $select expression.

See Use of the $select query parameter.

Example:

http://resource?$select=SystemType,Status
$skip=<integer>

Applies to Resource Collections. Returns a subset of the members in a Resource Collection. This paging query parameter defines the number of Members in the Resource Collection to skip.

Example:

http://resourcecollection?$skip=5
$top=<integer>

Applies to Resource Collections. Defines the number of members to show in the response.

Minimum value is 1. By default, returns all members.

Example:

http://resourcecollection?$top=30

7.3.1. Use of the $expand query parameter

The $expand query parameter allows a client to request a response that includes not only the requested resource, but also includes the contents of the subordinate or hyperlinked resources. The definition of this query parameter follows the OData-Protocol specification.

The $expand query parameter has a set of possible options that determine which hyperlinks in a resource are included in the expanded response. Some resources may already be expanded due to the resource's schema annotation AutoExpand, such as the Temperature object in the Thermal resource.

The Redfish-supported options for the $expand query parameter are listed in the following table. The service may implement some of these options but not others. Any other supported syntax for $expand is outside the scope of this specification.

Option Description Example
asterisk (*) Shall expand all hyperlinks. http://resource?$expand=*
$levels The number of levels the service should cascade the $expand operation. The default level shall be 1.
For example, $levels=2 expands both:
  • The hyperlinks in the current resource (level 1).
  • The hyperlinks in the resulting expanded resources (level 2).
 http://resourcecollection?$expand=.($levels=2)
period (.) Shall expand all hyperlinks not in the Links Property section of the resource. http://resourcecollection?$expand=.
tilde (~) Shall expand all hyperlinks found in the Links Property section of the resource. http://resourcecollection?$expand=~

Examples of $expand usage include:

When services execute $expand, they may omit some of the referenced resource's properties.

When clients use $expand, they should be aware that the payload may increase beyond what can be sent in a single response.

If a service cannot return the payload due to its size, it shall return HTTP 507 status code.

The following is an example showing the RoleCollection resource being expanded with the level set to 1:

{
    "@odata.id": "/redfish/v1/AccountService/Roles",
    "@odata.type": "#RoleCollection.RoleCollection",
    "Name": "Roles Collection",
    "Members@odata.count": 3,
    "Members": [
        {
            "@odata.id": "/redfish/v1/AccountService/Roles/Administrator",
            "@odata.type": "#Role.v1_1_0.Role",
            "Id": "Administrator",
            "Name": "User Role",
            "Description": "Admin User Role",
            "IsPredefined": true,
            "AssignedPrivileges": [
                "Login",
                "ConfigureManager",
                "ConfigureUsers",
                "ConfigureSelf",
                "ConfigureComponents"
            ]
        },
        {
            "@odata.id": "/redfish/v1/AccountService/Roles/Operator",
            "@odata.type": "#Role.v1_1_0.Role",
            "Id": "Operator",
            "Name": "User Role",
            "Description": "Operator User Role",
            "IsPredefined": true,
            "AssignedPrivileges": [
                "Login",
                "ConfigureSelf",
                "ConfigureComponents"
            ]
        },
        {
            "@odata.id": "/redfish/v1/AccountService/Roles/ReadOnly",
            "@odata.type": "#Role.v1_1_0.Role",
            "Id": "ReadOnly",
            "Name": "User Role",
            "Description": "ReadOnly User Role",
            "IsPredefined": true,
            "AssignedPrivileges": [
                "Login",
                "ConfigureSelf"
            ]
        }
    ]
}

7.3.2. Use of the $select query parameter

The $select query parameter indicates that the implementation should return a subset of the resource's properties that match the $select expression. If a request omits the $select query parameter, the response returns all properties by default. The definition of this query parameter follows the OData-Protocol specification.

The $select expression shall not affect the resource itself.

The $select expression defines a comma-separated list of properties to return in the response body.

The syntax for properties in object types shall be the object and property names concatenated with a slash (/).

An example of $select usage is:

GET /redfish/v1/Systems/1$select=Name,SystemType,Status/State

When services execute $select, they shall return all requested properties of the referenced resource. The @odata.id and @odata.type properties shall be in the response payload and contain the same values as if $select was not performed. If the @odata.context property is supported, it shall be in the response payload and should be in the Context property recommended format. If the @odata.etag property is supported, it shall be in the response payload and contain the same values as if $select was not performed.

Any other supported syntax for $select is outside the scope of this specification.

7.3.3. Use of the $filter query parameter

The $filter parameter allows a client to request a subset of the Resource Collection's members based on the $filter expression. The definition of this query parameter follows the OData-Protocol specification.

The $filter query parameter defines a set of properties and literals with an operator.

A literal value can be:

If the literal value does not match the data type for the specified property, the service should reject $filter requests with the HTTP 400 status code.

The $filter section of the OData ABNF components specification contains the grammar for the allowable syntax of the $filter query parameter, with the additional restriction that only built-in filter operations are supported.

The following table lists the Redfish-supported values for the $filter query parameter. Any other supported syntax for $filter is outside the scope of this specification.

Value Description Example
() Precedence grouping operator. (Status/State eq 'Enabled' and Status/Health eq 'OK') or SystemType eq 'Physical'
and Logical and operator. ProcessorSummary/Count eq 2 and MemorySummary/TotalSystemMemoryGiB gt 64
eq Equal comparison operator. ProcessorSummary/Count eq 2
ge Greater than or equal to comparison operator. ProcessorSummary/Count ge 2
gt Great than comparison operator. ProcessorSummary/Count gt 2
le Less than or equal to comparison operator. MemorySummary/TotalSystemMemoryGiB le 64
lt Less than comparison operator. MemorySummary/TotalSystemMemoryGiB lt 64
ne Not equal comparison operator. SystemType ne 'Physical'
not Logical negation operator. not (ProcessorSummary/Count eq 2)
or Logical or operator. ProcessorSummary/Count eq 2 or ProcessorSummary/Count eq 4

When evaluating expressions, services shall use the following operator precedence:

If the service receives an unsupported $filter query parameter, it shall reject the request and return the HTTP 501 status code.

The HEAD method differs from the GET method in that it shall not return message body information.

However, the HEAD method completes the same authorization checks and returns all the same meta information and status codes in the HTTP headers as a GET method.

Services may support the HEAD method to:

Services may support the HEAD method to verify resource accessibility.

Services shall not support any other use of the HEAD method.

The HEAD method shall be idempotent in the absence of outside changes to the resource.

7.5. Data modification requests

To create, modify, and delete resources, clients issue the following operations:

The following clauses describe the success and error response requirements common to all data modification requests.

7.5.1. Modification success responses

For create operations, the response from the service, after the create request succeeds, should be one of these responses:

For update, replace, and delete operations, the response from the service, after successful modification, should be one of the following responses:

For details on success responses to action requests, see POST (action).

7.5.2. Modification error responses

If the resource exists but does not support the requested operation, services may return the HTTP 405 status code.

Otherwise, if the service returns a client 4xx or service 5xx status code, the service encountered an error and the resource shall not have been modified or created as a result of the operation.

7.6. PATCH (update)

To update a resource's properties, the service shall support the PATCH method.

The request body defines the changes to make to one or more properties in the resource that the request URI references. The PATCH request does not change any properties that are not in the request body. The service shall ignore OData annotations in the request body, such as Resource identifier, type, and ETag properties. Services may accept a PATCH with an empty JSON object, which indicates that the service should make no changes to the resource.

When modification succeeds, the response may contain a representation of the updated resource. See Modification success responses.

To gain the protection semantics of an ETag, the service shall use the If-Match or If-None-Match header and not the @odata.etag property value for that protection.

The implementation may reject the update on certain properties based on its own policies and, in this case, not perform the requested update. For the following exception cases, services shall return the following HTTP status codes and other information:

Exception case The service returns
Modify several properties where one or more properties can never be updated.
For example, when a property is read-only, unknown, or unsupported.
  • The HTTP 200 status code.
  • A resource representation with a message annotation that lists the non-updatable properties.
  • The service may update other properties in the resource.
Modify a single property that can never be updated.
For example, a property that is read-only, unknown, or unsupported.
  • The HTTP 400 status code.
  • A resource representation with a message annotation that shows the non-updatable property.
Modify a resource or all properties that can never be updated.
  • The HTTP 405 status code.
A client PATCH request against a Resource Collection.
  • The HTTP 405 status code.
A client only provides OData annotations.

In the absence of outside changes to the resource, the PATCH operation should be idempotent, although the original ETag value may no longer match.

7.6.1. PATCH on array properties

There are three possible styles of array properties in a Resource, which are detailed in the Array properties clause.

Within a PATCH request, the service shall accept null to remove an element, and accept an empty object {} to leave an element unchanged. Array properties using the fixed or variable length style will remove those elements, while array properties using the rigid style will replace removed elements with null elements. A service may indicate the maximum size of an array by padding null elements at the end of the array sequence.

When processing a PATCH request, the order of operations shall be:

A PATCH request with fewer elements than currently exist in the array shall remove the remaining elements of the array.

For example, a fixed length style array of 'Flavors' indicates the service supports a maximum of six elements (by padding the array with null elements), with four populated. 

  "Flavors": [ "Chocolate", "Vanilla", "Mango", "Strawberry", null, null ]

A client could issue the following PATCH request to remove Vanilla, replace Strawberry with Cherry, and add Coffee and Banana to the array, while leaving the other elements unchanged.

  "Flavors": [ {}, null, {}, "Cherry", "Coffee", "Banana" ]

The resulting array after the PATCH is:

  "Flavors": [ "Chocolate", "Mango", "Cherry", "Coffee", "Banana", null ]

7.7. PUT (replace)

To completely replace a resource, services may support the PUT method. The service may add properties to the response resource that the client omits from the request body, the resource definition requires, or the service normally supplies.

The PUT operation should be idempotent in the absence of outside changes to the resource, with the possible exception that the operation might change ETag values.

When the replace operation succeeds, the response may contain a resource representation after the replacement occurs. See Modification success responses.

The following list contains the exception cases for PUT:

7.8. POST (create)

To create a new resource, services shall support the POST method on Resource Collections.

The POST request is submitted to the Resource Collection to which the new resource will belong. When the create operation succeeds, the response may contain the new resource representation. See Modification success responses.

The body of the create request contains a representation of the object to create. The service may ignore any service-controlled properties, such as Id, which would force the service to overwrite those properties. Additionally, the service shall set the Location header in the response to the URI of the new resource.

7.9. DELETE (delete)

To remove a resource, the service shall support the DELETE method.

When the delete operation succeeds, the response may contain the resource representation after the deletion occurs. See Modification success responses.

7.10. POST (Action)

Services shall support the POST method to send actions to Resources.

To request actions on a Resource, send the HTTP POST method to the URI of the action. The target property in the Resource's Actions property shall contain the URI of the action. The URI of the action shall be in the format:

ResourceUri/Actions/QualifiedActionName

where

Variable Description
ResourceUri The URI of the resource that supports the action.
Actions The name of the property that contains the actions for a resource, as defined by this specification.
QualifiedActionName The qualified name of the action. Includes the namespace.

To determine the available actions and the valid parameter values for those actions, clients can query a Resource directly.

Clients provide parameters for the action as a JSON object within the request body of the POST operation. See the Actions property clause for information about the structure of the request and required parameters. Some parameter information may require that the client examine the Redfish Schema that corresponds to the Resource.

The service may ignore unsupported parameters provided by the client. If an action does not have any required parameters, the service should accept an empty JSON object in the HTTP body for the action request.

To indicate the success or failure of the action request processing, the service may return a response with one of the following HTTP status codes and additional information:

To indicate HTTP status code Additional information
The action request succeeds. 200 The JSON message body, as described in Error responses, with a message that indicates success or any additional relevant messages. If the action was successfully processed and completed without errors, warnings, or other notifications for the client, the service should return the Success message from the base message registry in the code property in the response body.
The action request may require extra time to process. 202 A Location response header set to the URI of a Task Monitor.
The action request succeeds. 204 No JSON message body.
The client did not provide all required parameters. 400 The response may contain a JSON object, as described in Error responses, which details the error or errors.
The client provides a parameter that the service does not support, and the service does not ignore unsupported parameters. 400 The response may contain a JSON object, as described in Error responses, which details the error or errors.
An error was detected and the action request was not processed. 400 or greater The response may contain a JSON object, as described in Error responses, which details the error or errors.

If an action requested by the client will have no effect, such as performing a reset of a ComputerSystem where the parameter ResetType is set to On and the ComputerSystem is already On, the service should respond with an HTTP 200 status code and return the NoOperation message, defined in the Base Message Registry.

Example successful action response:

{
    "error": {
        "code": "Base.1.0.Success",
        "message": "Request completed successfully",
        "@Message.ExtendedInfo": [
            {
                "@odata.type": "#Message.v1_0_0.Message",
                "MessageId": "Base.1.0.Success",
                "Message": "completed successfully Request",
                "Severity": "OK",
                "Resolution": "None"
            }
        ]
    }
}

7.11. Operation apply time

Services may accept the @Redfish.OperationApplyTime annotation in the POST (create), DELETE (delete), or POST (action) request body. This annotation enables the client to control when an operation is carried out.

For example, if the client wants to delete a particular Volume resource, but can only safely do so when a reset occurs, the client can use this annotation to instruct the service to delete the Volume on the next reset.

If multiple operations are pending, the service shall process them in the order in which the service receives them.

Services that support the @Redfish.OperationApplyTime annotation for create and delete operations on a Resource Collection shall include the @Redfish.OperationApplyTimeSupport response annotation for the Resource Collection.

The following example response for a Resource Collection supports the @Redfish.OperationApplyTime annotation in the create and delete requests:

{
    "@odata.id": "/redfish/v1/Systems/1/Storage/SATAEmbedded/Volumes",
    "@odata.type": "#VolumeCollection.VolumeCollection",
    "Name": "Storage Volume Collection",
    "Description": "Storage Volume Collection",
    "Members@odata.count": 2,
    "Members": [
        {
            "@odata.id": "/redfish/v1/Systems/1/Storage/SATAEmbedded/Volumes/1"
        },
        {
            "@odata.id": "/redfish/v1/Systems/1/Storage/SATAEmbedded/Volumes/2"
        }
    ],
    "@Redfish.OperationApplyTimeSupport": {
        "@odata.type": "#Settings.v1_2_0.OperationApplyTimeSupport",
        "SupportedValues": [ "Immediate", "OnReset" ]
    }
}

In the previous example, a client can annotate their create request body on the VolumeCollection itself, or a delete operation on the Volumes within the VolumeCollection.

The following sample request deletes a Volume on the next reset:

DELETE /redfish/v1/Systems/1/Storage/SATAEmbedded/Volumes/2 HTTP/1.1
Content-Type: application/json;charset=utf-8
Content-Length: <computed length>
OData-Version: 4.0

{
    "@Redfish.OperationApplyTime": "OnReset"
}

Services that support the @Redfish.OperationApplyTime annotation for an action shall include the @Redfish.OperationApplyTimeSupport response annotation for the action.

The following example response for a ComputerSystem resource supports the @Redfish.OperationApplyTime annotation in the reset action request:

{
    "@odata.id": "/redfish/v1/Systems/1",
    "@odata.type": "#ComputerSystem.v1_5_0.ComputerSystem",
    "Actions": {
        "#ComputerSystem.Reset": {
            "target": "/redfish/v1/Systems/1/Actions/ComputerSystem.Reset",
            "ResetType@Redfish.AllowableValues": [
                "On",
                "ForceOff",
                "ForceRestart",
                "Nmi",
                "ForceOn",
                "PushPowerButton"
            ],
            "@Redfish.OperationApplyTimeSupport": {
                "@odata.type": "#Settings.v1_2_0.OperationApplyTimeSupport",
                "SupportedValues": [ "Immediate", "AtMaintenanceWindowStart" ],
                "MaintenanceWindowStartTime": "2017-05-03T23:12:37-05:00",
                "MaintenanceWindowDurationInSeconds": 600,
                "MaintenanceWindowResource": {
                    "@odata.id": "/redfish/v1/Systems/1"
                }
            }
        }
    },
    ...
}

In the previous example, a client can annotate their reset action request body on the ComputerSystem in the payload.

The following sample request completes a reset at the start of the next maintenance window:

POST /redfish/v1/Systems/1/Actions/ComputerSystem.Reset HTTP/1.1
Content-Type: application/json;charset=utf-8
Content-Length: <computed length>
OData-Version: 4.0

{
    "ResetType": "ForceRestart",
    "@Redfish.OperationApplyTime": "AtMaintenanceWindowStart"
}

Services that support the @Redfish.OperationApplyTime annotation for a Resource Collection or action shall create a Task, and respond with the HTTP 202 status code with a Location header set to the URI of a Task resource, if the client's request body contains @Redfish.OperationApplyTime in the request.

The Settings Redfish Schema defines the structure of the @Redfish.OperationApplyTimeSupport object and the @Redfish.OperationApplyTime annotation value.

8. Service responses

This clause describes the responses that Redfish Services can send to clients.

8.1. Response headers

HTTP defines headers that can be used in response messages. The following table defines those headers and their requirements for Redfish Services.

Header Required Supported values Description
OData-Version Yes 4.0 The OData version of the payload to which the response conforms.
Content-Type Yes RFC 7231 The type of representation used in the message body. Services shall specify a Content-Type of application/json when returning resources as JSON, and application/xml when returning metadata as XML. ;charset=utf-8 shall be appended to the Content-Type if specified in the chosen media-type in the Accept header for the request.
Content-Encoding No RFC 7231 The encoding that has been performed on the media type.
Content-Length No RFC 7231 The size of the message body. An optional means of indicating size of the body uses Transfer-Encoding: chunked, that does not use the Content-Length header. If a service does not support Transfer-Encoding and needs Content-Length instead, the service shall respond with status code 411.
ETag Conditional RFC 7232 An identifier for a specific version of a resource, often a message digest. The ETag header shall be included on responses to GETs of ManagerAccount resources.
Server Yes RFC 7231 A product token and its version. Multiple product tokens may be listed.
Link Yes See Link header Link headers shall be returned as described in the clause on Link headers.
Location Conditional RFC 7231 A URI that can be used to request a representation of the resource. Shall be returned if a new resource was created. Location and X-Auth-Token shall be included on responses that create user sessions.
Cache-Control Yes RFC 7234 Shall be supported and indicates whether a response can or cannot be cached.
Via No RFC 7230 Defines the network hierarchy and recognizes message loops. Each pass inserts its own Via header.
Max-Forwards No RFC 7231 Limits gateway and proxy hops. Prevents messages from remaining in the network indefinitely.
Access-Control-Allow-Origin Yes W3C CORS, Section 5.1 Prevents or allows requests based on originating domain. Used to prevent CSRF attacks.
Allow Yes POST, PUT, PATCH, DELETE, GET, HEAD Shall be returned with a 405 (Method Not Allowed) response to indicate the valid methods for the request URI. Shall be returned with any GET or HEAD operation to indicate the other allowable operations for this resource.
WWW-Authenticate Yes RFC 7235, Section 4.1 Required for Basic and other optional authentication mechanisms. See the Security details clause for details.
X-Auth-Token Yes Opaque encoded octet strings Used for authentication of user sessions. The token value shall be indistinguishable from random.
Retry-After No RFC 7231, Section 7.1.3 Used to inform a client how long to wait before requesting the Task information again.

The Link header provides metadata information on the accessed resource in response to a HEAD or GET operation. The information can contain items such as hyperlinks from the resource and JSON Schemas that describe the resource.

Below is an example of the Link headers of a ManagerAccount with a role of Administrator that has a Settings Annotation.

Link: </redfish/v1/AccountService/Roles/Administrator>; path=/Links/Role
Link: <http://redfish.dmtf.org/schemas/Settings.json>
Link: </redfish/v1/JsonSchemas/ManagerAccount.v1_0_2.json>; rel=describedby

A Link header containing rel=describedby shall be returned on GET and HEAD requests. If the referenced JSON Schema is a versioned schema, it shall match the version contained in the value of the @odata.type property returned in this resource.

A Link header satisfying annotations should be returned on GET and HEAD requests.

8.2. Status codes

HTTP defines status codes that are used in responses. The status codes themselves provide general information about how the request was processed, such as whether the request was successful, if the client provided bad information, or the service encountered an error when performing the request.

NOTE: Refer to the Security details clause for security implications of extended errors.

The following table lists HTTP status codes that have meaning or usage defined for a Redfish Service, or are otherwise referenced by this specification. Other codes may be returned by the service as appropriate, and their usage is implementation-specific. See the description column for usage and additional requirements imposed by this specification.

HTTP Status Code Description
200 OK The request was successfully completed and includes a representation in its body.
201 Created A request that created a new resource was completed successfully. The Location header shall be set to the canonical URI for the newly created resource. A representation of the newly created resource may be included in the response body.
202 Accepted The request has been accepted for processing, but the processing has not been completed. The Location header shall be set to the URI of a Task Monitor that can later be queried to determine the status of the operation. A representation of the Task resource may be included in the response body.
204 No Content The request succeeded, but no content is being returned in the body of the response.
301 Moved Permanently The requested resource resides under a different URI.
302 Found The requested resource resides temporarily under a different URI.
304 Not Modified The service has performed a conditional GET request where access is allowed, but the resource content has not changed. Conditional requests are initiated using the headers If-Modified-Since and/or If-None-Match (see HTTP 1.1, sections 14.25 and 14.26) to save network bandwidth if there is no change.
400 Bad Request The request could not be processed because it contains missing or invalid information (such as validation error on an input field, a missing required value, and so on). An extended error shall be returned in the response body, as defined in clause Error responses.
401 Unauthorized The authentication credentials included with this request are missing or invalid.
403 Forbidden The service recognized the credentials in the request, but those credentials do not possess authorization to perform this request. This code is also returned when the user credentials provided need to be changed before access to the service can be granted. See the Security clause for more details.
404 Not Found The request specified a URI of a resource that does not exist.
405 Method Not Allowed The HTTP verb specified in the request (e.g., DELETE, GET, HEAD, POST, PUT, PATCH) is not supported for this request URI. The response shall include an Allow header, that provides a list of methods that are supported by the resource identified by the URI in the client request.
406 Not Acceptable The Accept header was specified in the request and the resource identified by this request is not capable of generating a representation corresponding to one of the media types in the Accept header.
409 Conflict A creation or update request could not be completed, because it would cause a conflict in the current state of the resources supported by the platform (for example, an attempt to set multiple properties that work in a linked manner using incompatible values).
410 Gone The requested resource is no longer available at the service and no forwarding address is known. This condition is expected to be considered permanent. Clients with hyperlink editing capabilities should delete references to the URI in the client request after user approval. If the service does not know, or has no facility to determine, whether or not the condition is permanent, the status code 404 (Not Found) should be used instead. This response is cacheable unless indicated otherwise.
411 Length Required The request did not specify the length of its content using the Content-Length header (perhaps Transfer-Encoding: chunked was used instead). The addressed resource requires the Content-Length header.
412 Precondition Failed The precondition (such as OData-Version, If-Match or If-Not-Modified headers) check failed.
415 Unsupported Media Type The request specifies a Content-Type for the body that is not supported.
428 Precondition Required The request did not provide the required precondition, such as an If-Match or If-None-Match header.
431 Request Header Field Too Large The service is unwilling to process the request because either an individual header field, or all the header fields collectively, are too large.
500 Internal Server Error The service encountered an unexpected condition that prevented it from fulfilling the request. An extended error shall be returned in the response body, as defined in clause Error responses.
501 Not Implemented The service does not (currently) support the functionality required to fulfill the request. This is the appropriate response when the service does not recognize the request method and is not capable of supporting the method for any resource.
503 Service Unavailable The service is currently unable to handle the request due to temporary overloading or maintenance of the service. A service may use this response to indicate that the request URI is valid, but the service is performing initialization or other maintenance on the resource. It may also use this response to indicate the service itself is undergoing maintenance, such as finishing initialization steps after reboot of the service.
507 Insufficient Storage The service is unable to build the response for the client due to the size of the response.

8.3. OData metadata responses

OData metadata describes resources, Resource Collections, capabilities, and service-dependent behavior to generic OData consumers with no specific understanding of this specification. Clients are not required to request metadata if they already have sufficient understanding of the target service. For example, clients are not required to request metadata to request and interpret a JSON representation of a resource that this specification defines.

A client is able to access the OData metadata via the /redfish/v1/$metadata URI.

A client is able to access the OData service document via the /redfish/v1/odata URI.

8.3.1. OData $metadata

The OData metadata describes top-level service resources and resource types according to OData-Schema. The OData metadata is represented as an XML document with an Edmx root element in the https://docs.oasis-open.org/odata/ns/edmx namespace with an OData version attribute set to 4.0.

  <edmx:Edmx xmlns:edmx="https://docs.oasis-open.org/odata/ns/edmx" Version="4.0">
    <!-- edmx:Reference and edmx:Schema elements go here -->
  </edmx:Edmx>
8.3.1.1. Referencing other schemas

The OData metadata shall include the namespaces for each of the Redfish Resource types, along with the RedfishExtensions.v1_0_0 namespace.

These references may use either:

  <edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/ServiceRoot_v1.xml">
    <edmx:Include Namespace="ServiceRoot"/>
    <edmx:Include Namespace="ServiceRoot.v1_0_0"/>
  </edmx:Reference>

  ...

  <edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/VirtualMedia_v1.xml">
    <edmx:Include Namespace="VirtualMedia"/>
    <edmx:Include Namespace="VirtualMedia.v1_0_0"/>
  </edmx:Reference>
  <edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/RedfishExtensions_v1.xml">
    <edmx:Include Namespace="RedfishExtensions.v1_0_0" Alias="Redfish"/>
  </edmx:Reference>

The service's OData metadata document shall include an EntityContainer that defines the top-level resources and Resource Collections.

8.3.1.2. Referencing OEM extensions

The OData metadata document may reference additional schema documents that describe OEM-specific extensions that the service uses.

For example, the OData metadata document may reference custom types for additional Resource Collections.

  <edmx:Reference Uri="http://contoso.org/Schema/CustomTypes">
    <edmx:Include Namespace="CustomTypes"/>
  </edmx:Reference>

8.3.2. OData service document

The OData service document serves as a top-level entry point for generic OData clients. More information about the OData service document can be found in the OData JSON Format specification.

{
    "@odata.context": "/redfish/v1/$metadata",
    "value": [
        {
            "name": "Service",
            "kind": "Singleton",
            "url": "/redfish/v1/"
        },
        {
            "name": "Systems",
            "kind": "Singleton",
            "url": "/redfish/v1/Systems"
        },
        ...
    ]
}

The service shall return the OData service document as a JSON object by using the application/json MIME type.

The JSON object shall contain the @odata.context context property set to /redfish/v1/$metadata.

The JSON object shall include a value property set to a JSON array that contains an entry for the service root and each resource that is a direct child of the service root.

Each JSON object entry includes:

Property Defines
name A user-friendly resource name of the resource.
kind The type of resource. Value is Singleton for all cases defined by Redfish.
url The relative URL for the top-level resource.

8.4. Resource responses

Services return resources and Resource Collections as JSON payloads by using the application/json MIME type. A service shall not break responses for a single resource into multiple results.

The format of these payloads is defined by the Redfish schema. See the Data model and Schema definition languages clauses for rules about the Redfish schema, and how it maps to JSON payloads.

8.5. Error responses

HTTP response status codes often do not provide enough information to enable deterministic error semantics. For example, if a client makes a PATCH call and some properties do not match while others are not supported, the HTTP 400 status code does not tell the client which values are in error. Error responses are used to provide the client more meaningful and deterministic error semantics.

To provide the client with as much information about the error as possible, a Redfish Service may provide multiple error responses in the HTTP response. Additionally, the service may provide Redfish standardized errors, OEM-defined errors, or both, depending on the implementation's ability to convey the most useful information about the underlying error.

An extended error response, which is a single JSON object, defines the error responses, with an error property, which contains the following properties.

Property Description
code String. Defines a MessageId from the Message Registry.
message Displays a human-readable error message that corresponds to the Message in the Message Registry.
@Message.ExtendedInfo Displays an array of Message objects. Describes one or more error messages. 
{
    "error": {
        "code": "Base.1.0.GeneralError",
        "message": "A general error has occurred.  See ExtendedInfo for more information.",
        "@Message.ExtendedInfo": [
            {
                "@odata.type": "#Message.v1_0_0.Message",
                "MessageId": "Base.1.0.PropertyValueNotInList",
                "RelatedProperties": [
                    "#/IndicatorLED"
                ],
                "Message": "The value Red for the property IndicatorLED is not in the list of acceptable values",
                "MessageArgs": [
                    "RED",
                    "IndicatorLED"
                ],
                "Severity": "Warning",
                "Resolution": "Remove the property from the request body and resubmit the request if the operation failed"
            },
            {
                "@odata.type": "#Message.v1_0_0.Message",
                "MessageId": "Base.1.0.PropertyNotWritable",
                "RelatedProperties": [
                    "#/SKU"
                ],
                "Message": "The property SKU is a read only property and cannot be assigned a value",
                "MessageArgs": [
                    "SKU"
                ],
                "Severity": "Warning",
                "Resolution": "Remove the property from the request body and resubmit the request if the operation failed"
            }
        ]
    }
}

9. Data model

One of the key tenets of Redfish is the separation of protocol from the data model. This separation makes the data both transport and protocol agnostic. By concentrating on the data transported in the payload of the protocol (in HTTP, it is the HTTP body), Redfish is also able to define the payload in any encoding and the data model is intended to be schema language agnostic. While Redfish is defined using JSON, it is intended to provide a common encoding type and helps to ensure property naming conventions that make it easier for developers in many languages such as JavaScript and Python. All of this helps the Redfish data model to be more easily accessible in modern tools and programming environments.

This clause describes common data model, resource, and Redfish Schema requirements.

9.1. Resources

A Resource is a single entity. Services return resources as JSON payloads by using the application/json MIME type.

Each resource shall be strongly typed and defined in a Redfish schema document, and identified in the response payload by a unique type identifier property.

Responses for a single resource shall contain the following properties:

Responses may also contain other properties defined within the schema for that resource type. Responses shall not include any properties not defined by that resource type.

9.2. Resource Collections

A Resource Collection is a set of resources that share the same schema definition. Services return Resource Collections as JSON payloads by using the application/json MIME type.

Resource Collection responses shall contain the following properties:

Responses for Resource Collections may contain the following properties:

Responses for Resource Collections shall not contain any other properties with the exception of payload annotations.

9.3. OEM Resources

OEMs and other third parties can extend the Redfish data model by creating new resource types. This is accomplished by defining an OEM schema for each resource type, and connecting instances of those Resources to the Resource Tree.

Companies, OEMs, and other organizations can define additional properties, hyperlinks, and actions for standard Redfish Resources using the Oem property in Resources, the Links Property, and actions.

While the information and semantics of these extensions are outside of the standard, the schema representing the data, the Resource itself, and the semantics around the protocol shall conform to the requirements in this specification. OEMs are encouraged to follow the design tenets and naming conventions in this specification when defining OEM Resources or properties.

9.4. Common data types

The following clause details the data types found throughout the Redfish data model.

9.4.1. Primitive types

The following are the primitive data types found in the data model:

Type Description
Boolean This value can be true or false.
Number A number with optional decimal point or exponent. Number properties may restrict the representation to be an integer or a number with decimal point.
String A sequence of characters enclosed with double quotes (").
Array A comma separated set of the above types enclosed with square braces ([ and ]). See the Array properties clause for additional information.
Object A set of properties enclosed with curly braces ({ and }). See the Structured properties clause for additional information.
Null The value null. This is used when the Service is unable to determine the property value, or if the schema has requirements around using null for other conditions.

When receiving values from the client, services should support other valid representations of the data in the specified JSON type. In particular, services should support valid integer and decimal values in exponential notation and integer values that contain a decimal point with no non-zero trailing digits.

9.4.2. GUID/UUID values

Globally Unique Identifier (GUID)/Universally Unique Identifier (UUID) values are unique identifier strings and shall use the format:

([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12})

9.4.3. Date-Time values

Date-Time values are strings according to the ISO 8601 extended format, including the time offset or UTC suffix. Date-Time values shall use the format:

YYYY-MM-DDThh:mm:ss[.SSS](Z|(+|-)HH:MM)

where

Variable or separator Description
YYYY The four digit year.
MM The two digit month (1 to 12).
DD The two digit day (1 to 31).
T The time separator. Shall be a capital T.
hh The two digit hour (0 to 23).
mm The two digit minute (0 to 59).
ss The two digit second (0 to 59).
SSS The decimal fraction of a second. One or more digits where the number of digits implies the precision.
Z The zero offset indicator. Shall be a capital Z.
HH The two digit hour offset (0 to 23).
MM The two digit minute offset (0 to 59).

For example, the value "2015-03-13T04:14:33+06:00" represents March 13, 2015 at 4:14:33 with a time offset of +06:00.

When the time of day is unknown or serves no purpose, the service shall report 00:00:00Z for the time of day value.

9.4.4. Duration values

Duration values are strings according to the ISO 8601 duration format. Duration values shall use the format:

P[yY][mM][wW][dD][T[hH][mM][s[.f]S]]

where

Variable Description
y The number of years.
m The number of months.
w The number of weeks.
d The number of days.
h The number of hours.
m The number of minutes.
s The number of seconds.
f The fractional seconds.

Each field is optional and may contain more than one digit.

For example, the following values represent the following durations:

Value Specifies a duration of
P3D Three days.
PT6H Six hours.
PT10S Ten seconds.
PT0.001S 0.001 seconds.
PT1H30M One hour and 30 minutes.

9.4.5. Reference properties

Reference properties are used to provide a reference to another Resource in the data model. Reference properties are JSON objects that contain an @odata.id property. The value of @odata.id is the URI of the Resource being referenced.

9.4.6. Array properties

Array properties contain a set of values or objects, and appear as JSON arrays within a response body. Array elements shall all contain values of the same data type.

There are three styles of arrays, regardless of the data type of the elements:

Services may pad an array property with null elements at the end of the sequence to indicate the array size to clients. This is useful for small fixed length arrays, and for variable or rigid arrays with a restrictive maximum size. Services should not pad array properties if the maximum array size is not restrictive. For example, an array property typically populated with two elements, that a service limits to a maximum of 16 elements, should not pad the array with 14 null elements.

9.4.7. Structured properties

Structured properties are JSON objects within a response body.

Some structured properties inherit from the Resource.v1_0_0.ReferenceableMember definition. Structured properties that follow this definition shall contain the MemberId and Resource identifier properties.

Because the definition of structured properties can evolve over time, clients need to be aware of the inheritance model that the different structured property definitions use.

For example, the Location definition in the Resource schema has gone through several iterations since the Resource.v1_1_0 namespace was introduced, and each iteration inherits from the previous version so that existing references in other schemas can leverage the new additions.

Structured property references need to be resolved for both local and external references.

A local reference is a Resource that has a structured property in its own schema, such as ProcessorSummary in the ComputerSystem Resource. In these cases, the type property for the Resource is the starting point for resolving the structured property definition.

To find the latest applicable version, clients can step the version of the Resource backwards.

For example, if a service returns #ComputerSystem.v1_4_0.ComputerSystem as the Resource type, a client can step backwards from ComputerSystem.v1_4_0, to ComputerSystem.v1_3_0, to ComputerSystem.v1_2_0, and so on, until it finds the ProcessorSummary structured property definition.

An external reference is a Resource that has a property that references a definition found in a different schema, such as Location in the Chassis Resource.

In these cases, clients can use the latest version of the external schema file as a starting point to resolve the structured property definition.

For example, if the latest version of the Resource schema is 1.6.0, a client can go backward from Resource.v1_6_0, to Resource.v1_5_0, to Resource.v1_4_0, and so on, until it finds the Location structured property definition.

9.4.8. Message object

A Message object provides additional information about an object, property, or error response.

A Message object is a JSON object with the following properties:

Property Type Required Defines
MessageId String Yes The error or message, which is not to be confused with the HTTP status code. Clients can use this code to access a detailed message from a message registry.
Message String No The human-readable error message that indicates the semantics associated with the error. This shall be the complete message, and not rely on substitution variables.
RelatedProperties An array of JSON pointers No The properties in a JSON payload that the message describes.
MessageArgs An array of strings No The substitution parameter values for the message. If the parameterized message defines a MessageId, the service shall include the MessageArgs in the response.
Severity String No The severity of the error.
Resolution String No The recommended actions to take to resolve the error.

Each instance of a Message object shall contain at least a MessageId, together with any applicable MessageArgs, or a Message property that defines the complete human-readable error message.

MessageIds identify specific messages that a message registry defines.

The MessageId property value shall be in the format:

RegistryName.MajorVersion.MinorVersion.MessageKey

where

Variable Description
RegistryName The name of the registry. The registry name shall be Pascal-cased.
MajorVersion A positive integer. The major version of the registry.
MinorVersion A positive integer. The minor version of the registry.
MessageKey The human-readable key into the registry. The message key shall be Pascal-cased and shall not include spaces, periods, or special characters.

To search the message registry for a corresponding message, the client can use the MessageId.

The message registry approach has advantages for internationalization, because the registry can be translated easily, and lightweight implementation because large strings need not be included with the implementation.

The use of Base.1.0.GeneralError as a MessageId in ExtendedInfo is discouraged. If no better message exists or the ExtendedInfo array contains multiple messages, use Base.1.0.GeneralError only in the code property of the error object.

When an implementation uses Base.1.0.GeneralError in ExtendedInfo, the implementation should include a Resolution property with this error to indicate how to resolve the problem.

9.5. Properties

Every property included in a Redfish response payload shall be defined in the schema for that resource. The following attributes apply to all property definitions:

This clause also contains a set of common properties across all Redfish Resources. The property names in this clause shall not be used for any other purpose, even if they are not implemented in a particular resource.

9.5.1. Resource identifier (@odata.id) property

Resources in a response shall include an @odata.id property. The value of the identifier property shall be the Resource URI.

9.5.2. Resource type (@odata.type) property

All Resources in a response shall include an @odata.type type property. To support generic OData clients, all structured properties in a response should include an @odata.type type property. The value shall be a URL fragment that specifies the type of the resource and shall be in the format:

#Namespace.TypeName

where

Variable Description
Namespace The full namespace name of the Redfish Schema that defines the type. For Redfish Resources, the versioned namespace name.
TypeName The name of the Resource type.

An example of a Resource type value is #ComputerSystem.v1_0_0.ComputerSystem, where ComputerSystem.v1_0_0 denotes the version 1.0.0 namespace of ComputerSystem, and the type itself is ComputerSystem.

9.5.3. Resource ETag (@odata.etag) property

ETags enable clients to conditionally retrieve or update a Resource. Resources should include an @odata.etag property. For a Resource, the value shall be the ETag.

9.5.4. Resource context (@odata.context) property

Responses for a single Resource may contain an @odata.context property that describes the source of the payload.

If the @odata.context property is present, it shall be the context URL that describes the resource, according to OData-Protocol.

The context URL for a resource should be in the format:

/redfish/v1/$metadata#ResourceType

where ResourceType is the fully qualified name of the unversioned resource type. Redfish Resource definitions concatenate the Resource type namespace with a period (.) followed by the Resource type.

For example, the following context URL specifies that the results show a single ComputerSystem Resource:

{
    "@odata.context": "/redfish/v1/$metadata#ComputerSystem.ComputerSystem",
    ...
}

The context URL for a Resource may be in one of the other formats specified by OData-Protocol.

9.5.5. Id

The Id property of a Resource uniquely identifies the resource within the Resource Collection that contains it. The value of Id shall be unique across a Resource Collection. The Id property shall follow the definition for Id in the Resource schema.

9.5.6. Name

The Name property is used to convey a human-readable moniker for a resource. The type of the Name property shall be string. The value of Name is NOT required to be unique across resource instances within a Resource Collection. The Name property shall follow the definition for Name in the Resource schema.

9.5.7. Description

The Description property is used to convey a human-readable description of the resource. The Description property shall follow the definition for Description in the Resource schema.

9.5.8. MemberId

The MemberId property uniquely identifies an element within an array, where the element can be referenced by a reference property. The value of MemberId shall be unique across the array. The MemberId property shall follow the definition for MemberId in the Resource schema.

9.5.9. Count (Members@odata.count) property

The count property defines the total number of Resources, or members, that are available in a Resource Collection. The count property shall be named Members@odata.count and its value shall be the total number of members available in the Resource Collection. The $top or $skip query parameters shall not affect this count.

9.5.10. Members

The Members property of a Resource Collection identifies the members of the collection. The Members property is required and shall be returned in the response for any Resource Collection. The Members property shall be an array of JSON objects named Members. The Members property shall not be null. Empty collections shall be an empty JSON array.

9.5.11. Next link (Members@odata.nextLink) property

The value of the Next Link property shall be an opaque URL to a Resource, with the same @odata.type, which contains the next set of partial members from the original operation. The Next Link property shall only be present if the number of Members in the Resource Collection is greater than the number of members returned, and if the payload does not represent the end of the requested Resource Collection.

The Members@odata.count property value is the total number of Resources available if the client enumerates all pages of the Resource Collection.

9.5.12. Links

The Links property represents the hyperlinks associated with the Resource, as defined by that Resource's schema definition. All associated reference properties defined for a resource shall be nested under the Links property. All directly (subordinate) referenced properties defined for a resource shall be in the root of the resource.

The Links property shall be named Links and contain a property for each related Resource.

To navigate vendor-specific hyperlinks, the Links property shall also include an Oem property.

A reference to a single Resource is a JSON object that contains a single Resource identifier property. The name of this reference is the name of the relationship. The value of this reference is the URI of the referenced Resource.

{
    "Links": {
        "ManagedBy": {
            "@odata.id": "/redfish/v1/Chassis/Encl1"
        }
    }
}

A reference to a set of zero or more related Resources is an array of JSON objects. The name of this reference is the name of the relationship. Each element of the array is a JSON object that contains a Resource identifier property with the value of the URI of the referenced resource.

{
    "Links": {
        "Contains": [
            {
                "@odata.id": "/redfish/v1/Chassis/1"
            },
            {
                "@odata.id": "/redfish/v1/Chassis/Encl1"
            }
        ]
    }
}

9.5.13. Actions

The Actions property contains the actions supported by a Resource.

9.5.13.1. Action representation

Each supported action is represented as a property nested under Actions. The property name is constructed using the unique URI that identifies the action.

This property name shall be in the format

#ResourceType.ActionName

where

Variable Description
ResourceType The Resource where the action is defined.
ActionName The name of the action.

The client may use this fragment to identify the action definition in the referenced Redfish Schema document.

The property for the action is a JSON object and contains the following properties:

The OData JSON Format specification defines the target and title properties.

To specify the list of supported values for a parameter, the service may include the @Redfish.AllowableValues annotation.

For example, the following property defines the Reset action for a ComputerSystem:

{
    "#ComputerSystem.Reset": {
        "target": "/redfish/v1/Systems/1/Actions/ComputerSystem.Reset",
        "title": "Computer System Reset",
        "ResetType@Redfish.AllowableValues": [
            "On",
            "ForceOff",
            "GracefulRestart",
            "GracefulShutdown",
            "ForceRestart",
            "Nmi",
            "ForceOn",
            "PushPowerButton"
        ]
    },
    ...
}

Given this, the client could invoke a POST request to /redfish/v1/Systems/1/Actions/ComputerSystem.Reset with the following body:

POST /redfish/v1/Systems/1/Actions/ComputerSystem.Reset HTTP/1.1
Content-Type: application/json;charset=utf-8
Content-Length: <computed length>
OData-Version: 4.0

{
    "ResetType": "On"
}

The Resource may provide a separate @Redfish.ActionInfo Resource to describe the parameters and values that a particular instance or implementation supports. Use the @Redfish.ActionInfo annotation to specify the ActionInfo resource, which contains a URI to the @Redfish.ActionInfo resource for the action. See the Action Info annotation clause for details.

9.5.14. Oem

The Oem property is used for OEM extensions as defined in Resource Extensibility.

9.5.15. Status

The Status property represents the status of a Resource. The Status property shall follow the definition for Status in the Resource schema.

By having a common representation of status, clients can depend on consistent semantics. The Status property is capable of indicating the current state, health of the Resource, and the health of subordinate Resources.

9.6. Resource, schema, and property naming conventions

The Redfish interface is intended to be easily readable and intuitive. Thus, consistency helps the consumer who is unfamiliar with a newly discovered property understand its use. While this is no substitute for the normative information in the Redfish Specification and Redfish Schema, the following rules help with readability and client usage.

Standard Redfish Resources defined and published in the repository, or those created by others and republished, shall follow a set of naming conventions. These conventions are intended to ensure consistent naming and eliminate naming collisions. The resource name is used to construct both the type identifier property and the schema file name for each of the supported schema description languages.

Standard Redfish properties follow similar naming conventions, and should use a common definition when defined in multiple schemas across the Redfish data model. This consistency allows for code re-use across resources and increases interoperability. Existing property definitions should be leveraged for new resource definitions whenever possible.

The Resource, schema, and property naming rules are as follows:

Exceptions are allowed for the following cases:

For properties that have units, or other special meaning, a unit identifier should be appended to the name. The current list includes:

9.7. Resource extensibility

In the context of this clause, the term OEM refers to any company, manufacturer, or organization that is providing or defining an extension to the DMTF-published schema and functionality for Redfish. All Redfish-specified resources include an empty structured property called Oem whose value can be used to encapsulate one or more OEM-specified structured properties. This is predefined placeholder available to contain OEM-specific property definitions.

9.7.1. OEM property format and content

Each property contained within the Oem property shall be a JSON object. The name of the object (property) shall uniquely identify the OEM or organization that defines the properties contained by that object. This is described in more detail in the following clause. The OEM-specified object shall also include a type property that provides the location of the schema and the type definition for the property within that schema. The Oem property can simultaneously hold multiple OEM-specified objects, including objects for more than one company or organization.

The definition of any other properties that are contained within the OEM-specific complex type, along with the functional specifications, validation, or other requirements for that content is OEM-specific and outside the scope of this specification. While there are no Redfish-specified limits on the size or complexity of the OEM-specified elements within an OEM-specified JSON object, it is intended that OEM properties will typically only be used for a small number of simple properties that augment the Redfish Resource. If a large number of objects or a large quantity of data (compared to the size of the Redfish Resource) is to be supported, the OEM should consider having the OEM-specified object point to a separate resource for their extensions.

9.7.2. OEM property naming

The OEM-specified objects within the Oem property are named using a unique OEM identifier for the top of the namespace under which the property is defined. There are two specified forms for the identifier. The identifier shall be either an ICANN-recognized domain name (including the top-level domain suffix), with all dot '.' separators replaced with underscores '', or an IANA-assigned Enterprise Number prefaced with "EID". DEPRECATED: The identifier shall be either an ICANN-recognized domain name (including the top-level domain suffix), or an IANA-assigned Enterprise Number prefaced with "EID:".

Organizations using '.com' domain names may omit the '.com' suffix (e.g., Contoso.com would use 'Contoso' instead of 'Contoso_com', but Contoso.org would use 'Contoso_org' as their OEM property name). The domain name portion of an OEM identifier shall be considered to be case independent. That is, the text "Contoso_biz", "contoso_BIZ", "conTOso_biZ", and so on, all identify the same OEM and top-level namespace.

The OEM identifier portion of the property name may be followed by an underscore and any additional string to allow further creation of namespaces of OEM-specified objects as desired by the OEM, e.g., "Contoso_xxxx" or "EID_412_xxxx". The form and meaning of any text that follows the trailing underscore is completely OEM-specific. OEM-specified extension suffixes may be case sensitive, depending on the OEM. Generic client software should treat such extensions, if present, as opaque and not attempt to parse nor interpret the content.

There are many ways this suffix could be used, depending on OEM need. For example, the Contoso company may have a suborganization "Research", in which case the OEM-specified property name might be extended to be "Contoso_Research". Alternatively, it could be used to identify a namespace for a functional area, geography, subsidiary, and so on.

The OEM identifier portion of the name will typically identify the company or organization that created and maintains the schema for the property. However, this is not a requirement. The identifier is only required to uniquely identify the party that is the top-level manager of a namespace to prevent collisions between OEM property definitions from different vendors or organizations. Consequently, the organization for the top of the namespace may be different than the organization that provides the definition of the OEM-specified property. For example, Contoso may allow one of their customers, e.g., "CustomerA", to extend a Contoso product with certain CustomerA proprietary properties. In this case, although Contoso allocated the name "Contoso_customers_CustomerA" it could be CustomerA that defines the content and functionality under that namespace. In all cases, OEM identifiers should not be used except with permission or as specified by the identified company or organization.

9.7.3. OEM resource naming and URIs

Companies, OEMs, and other organizations can define additional resources and link to them from an Oem property found in a standard Redfish Resource. To avoid naming collisions with current or future standard Redfish schema files, the defining organization's name should be prepended to the resource (schema) name. For example, ContosoDisk would not conflict with a Disk resource or another OEM's disk-related resource.

To avoid URI collisions with other OEM resources and future Redfish standard resources, the URIs for OEM resources within the Redfish Resource Tree shall be in the form of:

*BaseUri*/Oem/*OemName*/*ResourceName*

where

For example, if Contoso defined a new resource called ContosoAccountServiceMetrics to be linked via the Oem property found at the URI /redfish/v1/AccountService, the OEM resource would have the URI /redfish/v1/AccountService/Oem/Contoso/AccountServiceMetrics.

9.7.4. OEM property examples

The following fragment presents some examples of naming and use of the Oem property as it might appear when accessing a resource. The example shows that the OEM identifiers can be of different forms, that OEM-specified content can be simple or complex, and that the format and usage of extensions of the OEM identifier is OEM-specific.

{
    "Oem": {
        "Contoso": {
            "@odata.type": "#Contoso.v1_2_1.AnvilTypes1",
            "slogan": "Contoso anvils never fail",
            "disclaimer": "* Most of the time"
        },
        "Contoso_biz": {
            "@odata.type": "#ContosoBiz.v1_1.RelatedSpeed",
            "speed" : "ludicrous"
        },
        "EID_412_ASB_123": {
            "@odata.type": "#OtherSchema.v1_0_1.powerInfoExt",
            "readingInfo": {
                "readingAccuracy": "5",
                "readingInterval": "20"
            }
        },
        "Contoso_customers_customerA": {
            "@odata.type" : "#ContosoCustomer.v2015.slingPower",
            "AvailableTargets" : [ "rabbit", "duck", "runner" ],
            "launchPowerOptions" : [ "low", "medium", "eliminate" ],
            "powerSetting" : "eliminate",
            "targetSetting" : "rabbit"
        }
    },
    ...
}

9.7.5. OEM actions

OEM-specific actions appear in the JSON payload as properties of the Oem object, nested under an Actions property.

{
    "Actions": {
        "Oem": {
            "#Contoso.Ping": {
                "target":"/redfish/v1/Systems/1/Actions/Oem/Contoso.Ping"
            }
        }
    },
    ...
}

The URI of the OEM action in the target property shall be in the form of:

*ResourceUri*/Actions/Oem/*QualifiedActionName*

where

9.8. Payload annotations

Resources, objects within a Resource, and properties may include additional annotations as properties with the name in the format:

[PropertyName]@Namespace.TermName

where

Variable Description
PropertyName The name of the property to annotate. If absent, the annotation applies to the entire JSON object, which may be an entire Resource.
Namespace The name of the namespace that defines the annotation term.
TermName The name of the annotation term to apply to the resource or property of the resource.

Services shall limit the annotation usage to the odata, Redfish, and Message namespaces. The OData JSON Format specification defines the odata namespace. The Redfish namespace is an alias for the RedfishExtensions.v1_0_0 namespace.

The client can get the definition of the annotation from the OData $metadata document, the HTTP Link header, or may ignore the annotation entirely, but should not fail reading the resource due to unrecognized annotations, including new annotations that the Redfish namespace defines.

9.8.1. Allowable values

To specify the list of allowable values for a parameter, clients can use the @Redfish.AllowableValues annotation for properties or action parameters.

To specify the set of allowable values, include a property with the name of the property or parameter, followed by @Redfish.AllowableValues. The property value is a JSON array of strings that define the allowable values for the parameter.

9.8.2. Extended information

The following clause describes the two methods of providing extended information.

9.8.2.1. Extended object information

To specify object-level status information, services may annotate a JSON object with the @Message.ExtendedInfo annotation.

{
    "@odata.id": "/redfish/v1/Managers/1/SerialInterfaces/1",
    "@odata.type": "#SerialInterface.v1_0_0.SerialInterface",
    "Name": "Managed Serial Interface 1",
    "Description": "Management for Serial Interface",
    "Status": {
        "State": "Enabled",
        "Health": "OK"
    },
    "InterfaceEnabled": true,
    "SignalType": "Rs232",
    "BitRate": "115200",
    "Parity": "None",
    "DataBits": "8",
    "StopBits": "1",
    "FlowControl": "None",
    "ConnectorType": "RJ45",
    "PinOut": "Cyclades",
    "@Message.ExtendedInfo": [
        {
            "MessageId": "Base.1.0.PropertyDuplicate",
            "Message": "The property InterfaceEnabled was duplicated in the request.",
            "RelatedProperties": [
                "#/InterfaceEnabled"
            ],
            "Severity": "Warning",
            "Resolution": "Remove the duplicate property from the request body and resubmit the request if the operation failed."
        }
    ]
}

The value of the property is an array of message objects.

9.8.2.2. Extended property information

Services may use @Message.ExtendedInfo, prepended with the name of the property to annotate an individual property in a JSON object with extended information:

{
    "@odata.id": "/redfish/v1/Managers/1/SerialInterfaces/1",
    "@odata.type": "#SerialInterface.v1_0_0.SerialInterface",
    "Name": "Managed Serial Interface 1",
    "Description": "Management for Serial Interface",
    "Status": {
        "State": "Enabled",
        "Health": "OK"
    },
    "InterfaceEnabled": true,
    "SignalType": "Rs232",
    "BitRate": 115200,
    "Parity": "None",
    "DataBits": 8,
    "StopBits": 1,
    "FlowControl": "None",
    "ConnectorType": "RJ45",
    "PinOut": "Cyclades",
    "PinOut@Message.ExtendedInfo": [
        {
            "MessageId": "Base.1.0.PropertyValueNotInList",
            "Message": "The value Contoso for the property PinOut is not in the list of acceptable values.",
            "Severity": "Warning",
            "Resolution": "Choose a value from the enumeration list that the implementation can support and resubmit the request if the operation failed."
        }
    ]
}

9.8.3. Action Info annotation

The Action Info annotation is used to convey the parameter requirements and allowable values on parameters for actions. This is done using @Redfish.ActionInfo term within the action representation. This term contains a URI to the ActionInfo Resource.

Example #ComputerSystem.Reset action with the @Redfish.ActionInfo annotation and Resource:

{
    "Actions": {
        "#ComputerSystem.Reset": {
            "target": "/redfish/v1/Systems/1/Actions/ComputerSystem.Reset",
            "@Redfish.ActionInfo": "/redfish/v1/Systems/1/ResetActionInfo"
        }
    },
    ...
}

The ResetActionInfo Resource contains a more detailed description of the parameters and the supported values. This Resource follows the ActionInfo schema definition.

{
    "@odata.id": "/redfish/v1/Systems/1/ResetActionInfo",
    "@odata.type": "#ActionInfo.v1_0_0.ActionInfo",
    "Id": "ResetActionInfo",
    "Name": "Reset Action Info",
    "Parameters": [
        {
            "Name": "ResetType",
            "Required": true,
            "DataType": "String",
            "AllowableValues": [
                "On",
                "ForceOff",
                "ForceRestart",
                "Nmi",
                "ForceOn",
               "PushPowerButton"
            ]
        }
    ]
}

9.9. Settings Resource

A Settings Resource is used to represent the future intended state of a Resource. Some Resources have properties that can be updated and the updates take place immediately; however, some properties need to be updated at a certain point in time, such as a system reset. While the Resource represents the current state, the Settings Resource represents the future intended state. The service represents properties of a Resource that can only be updated at a certain point in time using a @Redfish.Settings payload annotation. The Settings annotation contains a link to a subordinate Resource with the same schema definition. The properties within the Settings Resource contain the properties that are updated at a certain point in time.

For Resources that support a future state and configuration, the response shall contain a property with the @Redfish.Settings annotation. When a Settings annotation is used, the following conditions shall apply:

The Settings Resource includes several properties to help clients monitor when the Resource is consumed by the service and determine the results of applying the values, which may or may not have been successful.

Below is an example body for a resource that supports a Settings resource. A client is able to locate the URI of the Settings Resource using the SettingsObject property.

{
    "@Redfish.Settings": {
        "@odata.type": "#Settings.v1_0_0.Settings",
        "SettingsObject": {
            "@odata.id": "/redfish/v1/Systems/1/Bios/SD"
        },
        "Time": "2017-05-03T23:12:37-05:00",
        "ETag": "A89B031B62",
        "Messages": [
            {
                "MessageId": "Base.1.0.PropertyNotWritable",
                "RelatedProperties": [
                    "#/Attributes/ProcTurboMode"
                ]
            }
        ]
    },
    ...
}

A client may indicate its preference on when to apply the future configuration by including the @Redfish.SettingsApplyTime annotation in the request body when updating the Settings Resource.

Below is an example request body that shows a client configuring when the values in the Settings Resource are to be applied. In this case it is either on reset or during the specified maintenance window:

{
    "@Redfish.SettingsApplyTime": {
        "@odata.type": "#Settings.v1_1_0.PreferredApplyTime",
        "ApplyTime": "OnReset",
        "MaintenanceWindowStartTime": "2017-05-03T23:12:37-05:00",
        "MaintenanceWindowDurationInSeconds": 600
    },
    ...
}

9.10. Special Resource situations

There are some situations that arise with certain kinds of resources that need to exhibit common semantic behavior.

9.10.1. Absent resources

Resources may be absent or their state unknown at the time a client requests information about that resource. For resources that represent removable or optional components, absence provides useful information to clients, as it indicates a capability (e.g., an empty PCIe slot, DIMM socket, or drive bay) that would not be apparent if the resource simply did not exist. This also applies to resources that represent a limited number of items or unconfigured capabilities within an implementation, but this usage should be applied sparingly and should not apply to resources limited in quantity due to arbitrary limits (e.g., an implementation that limits SoftwareInventory to a maximum of 20 items should not populate 18 absent resources when only two items are present).

For resources that provide useful data in an absent state, and where the URI is expected to remain constant (such as when a DIMM is removed from a memory socket), the resource should exist, and should return a value of Absent for the State property in the Status object. In this circumstance, any required properties for which there is no known value shall be represented as null. Properties whose support is based on the configuration choice or the type of component installed (and therefore unknown while in the absent state), should not be returned. Likewise, subordinate resources for an absent resource should not be populated until their support can be determined (e.g., the Power and Thermal resources under a Chassis resource should not exist for an absent Chassis).

Client software should be aware that when absent resources are later populated, the updated resource may represent a different configuration or physical item, and previous data (including read-only properties) obtained from that resource may be invalid. For example, the Memory resource shows details about an single DIMM socket and the installed DIMM. When that DIMM is removed, the Memory resource remains as an absent resource to indicate the empty DIMM socket. Later, a new DIMM is installed in that socket, and the Memory resource represents data about this new DIMM, which could have completely different characteristics.

9.11. Registries

Registries are used in Redfish to optimize data being transferred from a Redfish Service.

Registry Resources are those Resources that assist the client in interpreting Redfish Resources beyond the Redfish Schema definitions. In registries, a identifier is used to retrieve more information about a given resource, event, message or other item. This can include other properties, property restrictions and the like. Registries are themselves Resources.

Redfish defines the following registry types:

9.12. Schema annotations

Schema annotations are used throughout the schema definitions of the data model to provide additional documentation for developers. This clause describes the different types of schema annotations used by the Redfish data model. See the Schema definition languages clause for information about how each of the annotations are implemented in their respective schema languages.

9.12.1. Description annotation

The Description annotation can be applied to any type, property, action, or parameter to provide a description of Redfish Schema elements suitable for end users or user interface help text.

A Description annotation shall be included on the following schema definitions:

9.12.2. Long Description annotation

The Long Description annotation can be applied to any type, property, action, or parameter to provide a formal, normative specification of the schema element. Where the Long Descriptions in the Redfish Schema contains normative language, the service shall be required to conform with the statement.

A Long Description annotation shall be included on the following schema definitions:

9.12.3. Resource Capabilities annotation

The Resource Capabilities annotation can be applied to Resources and Resource Collections to express the different type of HTTP operations a client is able to invoke on the given Resource or Resource Collection.

All schema definitions for Redfish Resources and Resource Collections shall include Resource Capabilities annotations.

9.12.4. Resource URI Patterns annotation

The Resource URI Patterns annotation is used to express the valid URI patterns for a given Resource or Resource Collection.

The strings for the URI patterns may use { and } characters to express parameters within a given URI pattern. Items between the { and } characters are treated as identifiers within the URI for given instances of a Redfish Resource. Clients interpret this as a string to be replaced to access a given resource. A URI pattern may contain multiple identifier terms to support multiple levels of nested Resource Collections. The identifier term in the URI pattern shall match the Id string property for the corresponding Resource, or the MemberId string property for the corresponding object within a Resource.

The following string is an example URI pattern that describes a Manager Account Resource: /redfish/v1/AccountService/Accounts/{ManagerAccountId}

Using the example above, {ManagerAccountId} would be replaced by the Id property of the corresponding ManagerAccount resource. If the Id property for a given Manager Account resource is John, then the full URI for that resource would be /redfish/v1/AccountService/Accounts/John.

The URI patterns are constructed based on the formation of the Resource Tree. When constructing the URI pattern for a subordinate resource, the URI pattern for the current resource is used, and appended. For example, the RoleCollection Resource is subordinate to AccountService. Because the URI pattern for AccountService is /redfish/v1/AccountService, the URI pattern for the RoleCollection Resource will be /redfish/v1/AccountService/Roles.

In some cases, the subordinate resource is found inside of a structured property of a Resource. In these cases, the name of the structured property is used in the URI pattern for the subordinate resource. For example, the CertificateCollection Resource is subordinate to the ManagerNetworkProtocol Resource from the HTTPS property. Because the URI pattern for ManagerNetworkProtocol is /redfish/v1/Managers/{ManagerId}/NetworkProtocol, the URI pattern for the CertificateCollection Resource will be /redfish/v1/Managers/{ManagerId}/NetworkProtocol/HTTPS/Certificates.

All schema definitions for Redfish Resources and Redfish Resource Collections shall be annotated with the Resource URI Patterns annotation.

All Redfish Resources and Redfish Resource Collections implemented by a service shall match the URI pattern described by the Resource URI Patterns annotation for their given definition.

9.12.5. Additional Properties annotation

The Additional Properties annotation is used to specify whether a type can contain additional properties outside of those defined in the schema. Types that do not support additional properties shall not contain properties beyond those described in the schema.

9.12.6. Permissions annotation

The Permissions annotation is used to specify if a client is allowed to modify the value of a property, or if the property is read-only.

A service may implement a modifiable property as read-only.

9.12.7. Required annotation

The Required annotation is used to specify that a property is required to be supported by services. Required properties shall be annotated with the Required annotation. All other properties are optional.

9.12.8. Required on Create annotation

The Required on Create annotation is used to specify that a property is required to be provided by the client on creation of the resource. Properties not annotated with the Required on Create annotation are not required to be provided by the client on a create operation.

9.12.9. Units of Measure annotation

In addition to following naming conventions, properties representing units of measure shall be annotated with the Units of Measure annotation to specify the units of measurement for the property.

The value of the annotation shall be a string that contains the case-sensitive "(c/s)" symbol of the unit of measure as listed in the Unified Code for Units of Measure (UCUM), unless the symbolic representation does not reflect common usage (e.g., RPM is commonly used to report fan speeds in revolutions-per-minute, but has no simple UCUM representation). For units with prefixes, the case-sensitive "(c/s)" symbol for the prefix as listed in UCUM should be prepended to the unit symbol. For example, Mebibyte (1024^2 bytes), which has the UCUM prefix "Mi" and symbol "By", would use MiBy as the value for the annotation. For values that also include rate information (e.g., megabits per second), the rate unit's symbol should be appended and use a "/" slash character as a separator (e.g., Mbit/s).

9.12.10. Expanded Resource annotation

The Expanded Resource annotation can be applied to a reference property to specify that the default behavior for the service is to include the contents of the related Resource or Resource Collection in responses. This behavior follows the same semantics of the expand query parameter with a level of 1.

Reference properties annotated with this term shall be expanded by the service, even if not requested by the client.

9.13. Versioning

As stated previously, a Resource can be an individual entity or a Resource Collection, which acts as a container for a set of Resources.

A Resource Collection does not contain any version information because it defines a single Members property, and the overall collection definition never grows over time.

A Resource has both unversioned and versioned definitions.

The unversioned definition of a Resource is used in references from other Resources to ensure there are no version dependencies between the definitions. The unversioned definition of a Resource contains no property information about the Resource.

The versioned definition of a Resource contains a set of properties, actions, and other definitions associated with the given Resource. The version of a Resource follows the following format:

vX.Y.Z

where

Variable Type Version Description
X Integer The major version A backward-incompatible change.
Y Integer The minor version A minor update. Redfish introduces new functionality but does not remove any functionality. The minor version preserves compatibility with earlier minor versions. For example, a new property introduces a new minor version of the resource.
Z Integer The errata version A fix in an earlier version. For example, a fix to a schema annotation on a property introduces an errata version of the resource.

9.14. Localization

The creation of separate localized copies of Redfish schemas and registries is allowed and encouraged. Localized schema and registry files may be submitted to the DMTF for republication in the Redfish Schema Repository.

Property names, parameter names, and enumeration values in the JSON response payload are never localized, but translated copies of those names may be provided as additional annotations in the localized schema for use by client applications. A separate file for each localized schema or registry shall be provided for each supported language. The English-language versions of Redfish schemas and registries shall be the normative versions, and alterations of meaning due to translation in localized versions of schemas and registries shall be forbidden.

Schemas and registries in languages other than English shall identify their language using the appropriate schema annotations. Descriptive property, parameter, and enumeration text not translated into the language specified shall be removed from localized versions. This removal allows for software and tools to combine normative and localized copies, especially when minor schema version differences exist.

10. File naming and publication

For consistency in publication and to enable programmatic access, all Redfish-related files shall follow a set of rules to construct the name of each file. The file name construction rules for Redfish Schema files are contained in the Schema definition languages clause, while construction rules for other file types are shown below.

10.1. Registry file naming

Redfish message or privilege registry files shall be named using the Registry name, following the format:

RegistryName.MajorVersion.MinorVersion.Errata.json

For example, version 1.0.2 of the Base message registry would be named "Base.1.0.2.json".

10.2. Profile file naming

The document describing a Profile follows the Redfish Schema file naming conventions. The file name format for Profiles shall be formatted as:

ProfileName.vMajorVersion_MinorVersion_Errata.json

For example, version 1.2.0 of the BasicServer profile would be named "BasicServer.v1_2_0.json". The file name shall include the Profile name and Profile version matching those property values within the document.

10.3. Dictionary file naming

The binary file describing a Redfish Device Enablement Dictionary follows the Redfish Schema file naming conventions for the schema definition language that the dictionary is converted from. As a single Dictionary file contains all minor revisions of the schema, only the major version is used in the file name. The file names for Dictionaries shall be formatted as:

DictionaryName_vMajorVersion.dict

For example, version 1.2.0 of the Chassis dictionary would be named "Chassis_v1.dict".

10.4. Localized file naming

Localized schemas and registries shall follow the same file naming conventions as the English language versions. When multiple localized copies are present in a repository (which will have the same file name), files in languages other than English shall be organized into subfolders named to match the ISO 639-1 language code for those files. English language files may be duplicated in an en subfolder for consistency.

10.5. DMTF Redfish file repository

All Redfish schemas, registries, dictionaries, and profiles published or republished by the DMTF's Redfish Forum are available from the DMTF website http://redfish.dmtf.org/ for download. Programs may access the repository using the durable URLs listed below. Programs incorporating remote repository access should implement a local cache to reduce latency, program requirements for Internet access and undue traffic burden on the DMTF website.

Organizations creating Redfish-related files such as OEM schemas, Redfish Interoperability Profiles, or Message Registries are encouraged to submit those files to the DMTF using the form at https://redfish.dmtf.org/redfish/portal for republication in the DMTF Redfish file repository.

The files are organized on the site in the following manner:

URL Folder contents
redfish.dmtf.org/schemas Current (most recent minor or errata) release of each schema file in CSDL, JSON Schema, and/or OpenAPI formats.
redfish.dmtf.org/schemas/v1 Durable URL for programmatic access to all v1.xx schema files. Every v1.xx minor or errata release of each schema file in CSDL, JSON Schema, OpenAPI formats.
redfish.dmtf.org/schemas/v1/{code} Durable URL for programmatic access to localized v1.xx schema files. Localized schemas are organized in subfolders using the 2-character ISO 639-1 language code as the {code} segment.
redfish.dmtf.org/schemas/archive Subfolders contain schema files specific to a particular version release.
redfish.dmtf.org/registries Current (most recent minor or errata) release of each registry file.
redfish.dmtf.org/registries/v1 Durable URL for programmatic access to all v1.xx registry files. Every v1.xx minor or errata release of each registry file.
redfish.dmtf.org/registries/v1/{code} Durable URL for programmatic access to localized v1.xx registry files. Localized schemas are organized in subfolders using the 2-character ISO 639-1 language code as the {code} segment.
redfish.dmtf.org/registries/archive Subfolders contain registry files specific to a particular version release.
redfish.dmtf.org/profiles Current release of each Redfish Interoperability Profile (.json) file and associated documentation.
redfish.dmtf.org/profiles/v1 Durable URL for programmatic access to all v1.xx Redfish Interoperability Profile (.json) files.
redfish.dmtf.org/profiles/archive Subfolders contain profile files specific to a particular profile version or release.
redfish.dmtf.org/dictionaries Durable URL for programmatic access to all v1.xx Redfish Device Enablement Dictionary files.
redfish.dmtf.org/dictionaries/v1 Durable URL for programmatic access to all v1.xx Redfish Device Enablement Dictionary files.
redfish.dmtf.org/dictionaries/archive Subfolders contain dictionary files specific to a particular version release.

11. Schema definition languages

Individual resources and their dependent types and actions are defined within a Redfish schema document. This clause describes how these documents are constructed in the following formats:

11.1. OData Common Schema Definition Language

OData Common Schema Definition Language (CSDL) is an XML schema format defined by the OData CSDL specification. The following clause describes how Redfish uses CSDL to describe Resources and Resource Collections.

11.1.1. File naming conventions for CSDL

Redfish CSDL schema files shall be named using the TypeName value, followed by "_v" and the major version of the schema. As a single CSDL schema file contains all minor revisions of the schema, only the major version is used in the file name. The file name shall be formatted as:

TypeName_vMajorVersion.xml

For example, version 1.3.0 of the Chassis schema would be named "Chassis_v1.xml".

11.1.2. Core CSDL files

The file Resource_v1.xml contains all base definitions for Resources, Resource Collections, and common properties such as Status.

The file RedfishExtensions_v1.xml contains the definitions for all Redfish types and annotations.

11.1.3. CSDL format

The outer element of the OData Schema representation document shall be the Edmx element, and shall have a Version attribute with a value of "4.0".

  <edmx:Edmx xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx" Version="4.0">
    <!-- edmx:Reference and edmx:DataService elements go here -->
  </edmx:Edmx>

The Referencing other CSDL files and CSDL Data Services clauses describe the items that are found within the Edmx element.

11.1.3.1. Referencing other CSDL files

CSDL files may reference types defined in other CSDL documents. This is done by including Reference tags.

The Reference element uses the Uri attribute to specify a CSDL file. The Reference element also contains one or more Include tags that specify the Namespace attribute containing the types to be referenced, along with an optional Alias attribute for that namespace.

Type definitions generally reference the OData and Redfish namespaces for common type annotation terms. Redfish CSDL files always use the Alias attribute on the following namespaces:

  <edmx:Reference Uri="http://docs.oasis-open.org/odata/odata/v4.0/cs01/vocabularies/Org.OData.Core.V1.xml">
    <edmx:Include Namespace="Org.OData.Core.V1" Alias="OData"/>
  </edmx:Reference>
  <edmx:Reference
    Uri="http://docs.oasis-open.org/odata/odata/v4.0/os/vocabularies/Org.OData.Measures.V1.xml">
    <edmx:Include Namespace="Org.OData.Measures.V1" Alias="Measures"/>
  </edmx:Reference>
  <edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/RedfishExtensions_v1.xml">
    <edmx:Include Namespace="RedfishExtensions.v1_0_0" Alias="Redfish"/>
    <edmx:Include Namespace="Validation.v1_0_0" Alias="Validation"/>
  </edmx:Reference>
  <edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/Resource_v1.xml">
    <edmx:Include Namespace="Resource"/>
    <edmx:Include Namespace="Resource.v1_0_0"/>
  </edmx:Reference>
11.1.3.2. CSDL Data Services

Structures, enums, and other definitions are defined within a namespace in CSDL. The namespace is defined through a Schema tag and using the Namespace attribute to declare the name of the namespace. Redfish uses namespaces to differentiate different versions of the schema. CSDL allows for structures to inherit from other structures, which allows for newer namespaces to only define the additional definitions. This behavior is described further in the Elements of CSDL namespaces clause.

The Schema element is a child of the DataServices element, which is a child of the Edmx element.

  <edmx:DataServices>
    <Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="MyTypes.v1_0_0">
      <!-- Type definitions for version 1.0.0 of MyTypes go here -->
    </Schema>

    <Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="MyTypes.v1_1_0">
      <!-- Type definitions for version 1.1.0 of MyTypes go here -->
    </Schema>
  </edmx:DataServices>

11.1.4. Elements of CSDL namespaces

The following clauses describe the different definitions that can be found within each namespace.

11.1.4.1. Qualified names

Many definitions in CSDL use references to qualified names. CSDL defines this as a string in the form of "Namespace.TypeName", where:

For example, if a reference is being made to MyType.v1_0_0.MyDefinition, this means the definition can be found in the MyType.v1_0_0 namespace with an element of the name MyDefinition.

11.1.4.2. Entity Type and Complex Type elements

The Entity Type and Complex Type elements are defined using the EntityType and ComplexType tags respectively. These elements are used to define a JSON structure and their set of properties. This is done by defining Property elements and Navigation Property element within the EntityType or ComplexType tags.

All Entity Types and Complex Types contain a Name attribute, which specifies the name of the definition.

Entity Types and Complex Types may have a BaseType attribute, which specifies a qualified name. When the BaseType attribute is used, all of the definitions of the referenced BaseType are made available to the Entity Type or Complex Type being defined.

All Resources and Resource Collections are defined with the Entity Type element. Resources inherit from Resource.v1_0_0.Resource, and Resource Collections inherit from Resource.v1_0_0.ResourceCollection.

Most structured properties are defined with the Complex Type element. Some are defined using the Entity Type element that inherits from Resource.v1_0_0.ReferenceableMember. The Entity Type element allows for references to be made using the Navigation Property element, whereas Complex Type element does not allow for this usage.

Example Entity Type and Complex Type element:

  <EntityType Name="TypeA" BaseType="Resource.v1_0_0.Resource">
    <Annotation Term="OData.Description" String="This is the description of TypeA."/>
    <Annotation Term="OData.LongDescription" String="This is the specification of TypeA."/>

    <!-- Property and Navigation Property definitions go here -->

  </EntityType>

  <ComplexType Name="PropertyTypeA">
    <Annotation Term="OData.Description" String="This is type used to describe a structured property."/>
    <Annotation Term="OData.LongDescription" String="This is the specification of the type."/>

    <!-- Property and Navigation Property definitions go here -->

  </ComplexType>
11.1.4.3. Action element

The Action element is defined using the Action tag. This element is used to define an action that can be performed on a Resource.

All Action elements contain a Name attribute, which specifies the name of the action.

In Redfish, all Action elements contain the IsBound attribute and is always set to true. This is used to indicate that the action appears as a member of a given structured type.

The Action element contains one or more Parameter elements that specify the Name and Type of each parameter.

Because all Action elements in Redfish use the term IsBound="true", the first parameter is called the "binding parameter" and specifies the structured type to which the action belongs. In Redfish, this is always going to be one of the following Complex Type elements:

The remaining Parameter elements describe additional parameters to be passed to the action. Parameters containing the term Nullable="false" are required to be provided in the action request.

  <Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="MyType">
    <Action Name="MyAction" IsBound="true">
      <Parameter Name="Thing" Type="MyType.Actions"/>
      <Parameter Name="Parameter1" Type="Edm.Boolean"/>
      <Parameter Name="Parameter2" Type="Edm.String" Nullable="false"/>
    </Action>

    <ComplexType Name="Actions">
      ...
    </ComplexType>
    ...
  </Schema>
11.1.4.4. Property element

Properties of Resources, Resource Collections, and structured properties are defined using the Property element. The Property tag is used to define a Property element inside of Entity Type and Complex Type elements.

All Property elements contain a Name attribute, which specifies the name of the property.

All Property elements contain a Type attribute specifies the data type. The Type attribute shall be one of the following:

Primitive data types shall be one of the following:

Type Meaning
Edm.Boolean True or False.
Edm.DateTimeOffset Date-time string.
Edm.Decimal Numeric values with fixed precision and scale.
Edm.Double IEEE 754 binary64 floating-point number (15-17 decimal digits).
Edm.Duration Duration string.
Edm.Guid GUID/UUID string.
Edm.Int64 Signed 64-bit integer.
Edm.String UTF-8 string.

Property elements may specify a Nullable attribute. If the value is false, value of null is not allowed as a value for the property. If the attribute is true or not specified, a value of null is allowed.

Example Property element:

  <Property Name="Property1" Type="Edm.String" Nullable="false">
    <Annotation Term="OData.Description" String="This is a property of TypeA."/>
    <Annotation Term="OData.LongDescription" String="This is the specification of Property1."/>
    <Annotation Term="OData.Permissions" EnumMember="OData.Permission/Read"/>
    <Annotation Term="Redfish.Required"/>
    <Annotation Term="Measures.Unit" String="Watts"/>
  </Property>

Reference properties of Resources, Resource Collections, and structured properties are defined using the Navigation Property element. The NavigationProperty tag is used to define a Navigation Property element inside of Entity Type and Complex Type elements.

All Navigation Property elements contain a Name attribute, which specifies the name of the property.

All Navigation Property elements contain a Type attribute specifies the data type. The Type attribute is a qualified name that references an Entity Type element. This can also be made into an array using the Collection term.

Navigation Property elements may specify a Nullable attribute. If the value is false, null is not allowed as a value for the property. If the attribute is true or not specified, a value of null is allowed.

Unless the reference property is to be expanded, all Navigation Properties in Redfish use the OData.AutoExpandReferences Annotation element to show that the reference is always available.

Example Navigation Property element:

  <NavigationProperty Name="RelatedType" Type="MyTypes.TypeB">
    <Annotation Term="OData.Description" String="This property references a related resource."/>
    <Annotation Term="OData.LongDescription" String="This is the specification of the related property."/>
    <Annotation Term="OData.AutoExpandReferences"/>
  </NavigationProperty>
11.1.4.6. Enum Type element

The Enum Type element is defined using the EnumType tag. This element is used to define a set of enumeration values, which may be applied to one or more properties.

All Enum Types contain a Name attribute, which specifies the name of the set of enumeration values.

Enum Types contain Member elements that define the members of the enumeration. The Member elements contain a Name attribute that specifies the string value of the member name.

  <EnumType Name="EnumTypeA">
    <Annotation Term="OData.Description" String="This is the EnumTypeA enumeration."/>
    <Annotation Term="OData.LongDescription" String="This is used to describe the EnumTypeA enumeration."/>
    <Member Name="MemberA">
      <Annotation Term="OData.Description" String="Description of MemberA"/>
    </Member>
    <Member Name="MemberB">
      <Annotation Term="OData.Description" String="Description of MemberB"/>
    </Member>
  </EnumType>
11.1.4.7. Annotation element

Annotations in CSDL are expressed using the Annotation element. The Annotation element can be applied to any schema element in CSDL. The following examples show how each of the different schema annotations used by Redfish are expressed in CSDL.

Terms with the prefix OData are defined in the OData Core Schema.

Terms with the prefix Measures are defined in OData Measures Schema.

Terms with the prefix Redfish are defined in RedfishExtensions Schema.

Example Description annotation:

  <Annotation Term="OData.Description" String="This property contains the user name for the account."/>

Example Long Description annotation:

  <Annotation Term="OData.LongDescription" String="This property shall contain the user name for the account."/>

Example Additional Properties annotation:

  <Annotation Term="OData.AdditionalProperties"/>

Example Permissions annotation (Read Only):

  <Annotation Term="OData.Permissions" EnumMember="OData.Permission/Read"/>

Example Permissions annotation (Read/Write):

  <Annotation Term="OData.Permissions" EnumMember="OData.Permission/ReadWrite"/>

Example Required annotation:

  <Annotation Term="Redfish.Required"/>

Example Required on Create annotation:

  <Annotation Term="Redfish.RequiredOnCreate"/>

Example Units of Measure annotation:

  <Annotation Term="Measures.Unit" String="MiBy"/>

Example Expanded Resource annotation:

  <Annotation Term="OData.AutoExpand"/>

Example Insert Capabilities Annotation (showing POST is not allowed):

  <Annotation Term="Capabilities.InsertRestrictions">
    <Record>
      <PropertyValue Property="Insertable" Bool="false"/>
    </Record>
  </Annotation>

Example Update Capabilities Annotation (showing PATCH and PUT are allowed):

  <Annotation Term="Capabilities.UpdateRestrictions">
    <Record>
      <PropertyValue Property="Updatable" Bool="true"/>
      <Annotation Term="OData.Description" String="Manager Accounts can be updated to change the password and other writable properties."/>
    </Record>
  </Annotation>

Example Delete Capabilities Annotation (showing DELETE is allowed):

  <Annotation Term="Capabilities.DeleteRestrictions">
    <Record>
      <PropertyValue Property="Deletable" Bool="true"/>
      <Annotation Term="OData.Description" String="Manager Accounts are removed with a Delete operation."/>
    </Record>
  </Annotation>

Example Resource URI Patterns Annotation:

  <Annotation Term="Redfish.Uris">
    <Collection>
      <String>/redfish/v1/AccountService/Accounts/{ManagerAccountId}</String>
    </Collection>
  </Annotation>

11.2. JSON Schema

The JSON Schema specification defines a JSON format for describing JSON payloads. The following clause describes how Redfish uses JSON Schema to describe Resources and Resource Collections.

11.2.1. File naming conventions for JSON Schema

Versioned Redfish JSON Schema files shall be named using the TypeName, following the format:

ResourceTypeName.vMajorVersion_MinorVersion_Errata.json

For example, version 1.3.0 of the Chassis schema would be named "Chassis.v1_3_0.json".

Unversioned Redfish JSON Schema files shall be named using the TypeName, following the format:

ResourceTypeName.json

For example, the unversioned definition of the Chassis schema would be named "Chassis.json".

11.2.2. Core JSON Schema files

The file odata-v4.json contains the definitions for common OData properties.

The file redfish-error.v1_0_0.json contains the payload definition of the Redfish error response.

The file redfish-schema-v1.json contains extensions to the JSON Schema used to define Redfish JSON Schema files.

The file Resource.json and its subsequent versioned definitions contain all base definitions for Resources, Resource Collections, and common properties such as Status.

11.2.3. JSON Schema format

Each JSON Schema file contains a JSON object to describe Resources, Resource Collections, or other definitions for the data model. The following terms can be found in the JSON object:

11.2.4. JSON Schema definitions body

This clause describes the types of definitions that can be found in the definitions term of a Redfish JSON Schema file.

11.2.4.1. Resource definitions in JSON Schema

To satisfy versioning requirements, the JSON Schema representation of each Resource has one unversioned schema file, and a set of versioned schema files.

The unversioned definition of a Resource contains an anyOf statement. This statement consists of an array of $ref terms, which point to the following:

The unversioned definition of a Resource also uses the uris term to express the allowable URIs for the resource, and the deletable, insertable, and updatable terms to express the capabilities of the resource.

Example unversioned Resource definition in JSON Schema:

{
    "ComputerSystem": {
        "anyOf": [
            {
                "$ref": "http://redfish.dmtf.org/schemas/v1/odata.v4_0_3.json#/definitions/idRef"
            },
            {
                "$ref": "http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_0_0.json#/definitions/ComputerSystem"
            },
            {
                "$ref": "http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_0_1.json#/definitions/ComputerSystem"
            },
            {
                "$ref": "http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_6_0.json#/definitions/ComputerSystem"
            }
        ],
        "deletable": true,
        "description": "The ComputerSystem schema represents a general purpose machine or system.",
        "insertable": false,
        "longDescription": "This resource shall be used to represent resources that represent a computing system.",
        "updatable": true,
        "uris": [
            "/redfish/v1/Systems/{ComputerSystemId}"
        ]
    },
    ...
}

The versioned definition of a Resource contains the property definitions for the given version of the Resource.

11.2.4.2. Enumerations in JSON Schema

Definitions for enumerations can consist of the following terms:

Example enumeration definition in JSON Schema:

{
    "IndicatorLED": {
        "enum": [
            "Lit",
            "Blinking",
            "Off"
        ],
        "enumDescriptions": {
            "Blinking": "The Indicator LED is blinking.",
            "Lit": "The Indicator LED is lit.",
            "Off": "The Indicator LED is off."
        },
        "enumLongDescriptions": {
            "Blinking": "This value shall represent the Indicator LED is in a blinking state where the LED is being turned on and off in repetition.",
            "Lit": "This value shall represent the Indicator LED is in a solid on state.",
            "Off": "This value shall represent the Indicator LED is in a solid off state."
        },
        "type": "string"
    },
    ...
}
11.2.4.3. Actions in JSON Schema

Versioned definitions of Resources contain a definition called Actions. This definition is a container with a set of terms that point to the different actions supported by the resource.

Example Actions definition:

{
    "Actions": {
        "additionalProperties": false,
        "description": "The available actions for this resource.",
        "longDescription": "This type shall contain the available actions for this resource.",
        "properties": {
            "#ComputerSystem.Reset": {
                "$ref": "#/definitions/Reset"
            }
        },
        "type": "object"
    },
    ...
}

Another definition within the same schema file is used to describe the action itself. This definition contains a term called parameters to describe the client request body. It also contains property definitions for the target and title properties shown in service response payloads for the Resource.

Example definition of an action:

{
    "Reset": {
        "additionalProperties": false,
        "description": "This action is used to reset the system.",
        "longDescription": "This action shall perform a reset of the ComputerSystem.",
        "parameters": {
            "ResetType": {
                "$ref": "http://redfish.dmtf.org/schemas/v1/Resource.json#/definitions/ResetType",
                "description": "The type of reset to be performed.",
                "longDescription": "This parameter shall define the type of reset to be performed."
            }
        },
        "properties": {
            "target": {
                "description": "Link to invoke action",
                "format": "uri",
                "type": "string"
            },
            "title": {
                "description": "Friendly action name",
                "type": "string"
            }
        },
        "type": "object"
    },
    ...
}

11.2.5. JSON Schema terms used by Redfish

The following JSON Schema terms are used to provide schema annotations for Redfish JSON Schema:

11.3. OpenAPI

The OpenAPI specification defines a format for describing JSON payloads, as well as the set of URIs a client is allowed to access on a service. The following clause describes how Redfish uses OpenAPI to describe Resources and Resource Collections.

11.3.1. File naming conventions for OpenAPI Schema

Versioned Redfish OpenAPI files shall be named using the TypeName, following the format:

ResourceTypeName.vMajorVersion_MinorVersion_Errata.yaml

For example, version 1.3.0 of the Chassis schema would be named "Chassis.v1_3_0.yaml".

Unversioned Redfish OpenAPI files shall be named using the TypeName, following the format:

ResourceTypeName.yaml

For example, the unversioned definition of the Chassis schema would be named "Chassis.yaml".

11.3.2. Core OpenAPI Schema files

The file odata-v4.yaml contains the definitions for common OData properties.

The file openapi.yaml contains the URI paths and their respective payload structures.

The file Resource.yaml and its subsequent versioned definitions contain all base definitions for Resources, Resource Collections, and common properties such as Status.

11.3.3. openapi.yaml

The YAML file openapi.yaml is the starting point for clients to understand the construct of the service. It contains the following terms:

The paths term contains an array of the possible URIs. For each URI, it also lists the possible methods. For each method, it lists the possible response bodies and request bodies.

Example paths entry for a Resource:

  /redfish/v1/Systems/{ComputerSystemId}:
    get:
      parameters:
      - description: The value of the Id property of the ComputerSystem resource
        in: path
        name: ComputerSystemId
        required: true
        schema:
          type: string
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_6_0.yaml#/components/schemas/ComputerSystem
          description: The response contains a representation of the ComputerSystem
            resource
        default:
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RedfishError'
          description: Error condition

Example paths entry for an action:

  /redfish/v1/Systems/{ComputerSystemId}/Actions/ComputerSystem.Reset:
    post:
      parameters:
      - description: The value of the Id property of the ComputerSystem resource
        in: path
        name: ComputerSystemId
        required: true
        schema:
          type: string
      requestBody:
        content:
          application/json:
            schema:
              $ref: http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_6_0.yaml#/components/schemas/ResetRequestBody
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RedfishError'
          description: The response contains the results of the Reset action
        '202':
          content:
            application/json:
              schema:
                $ref: http://redfish.dmtf.org/schemas/v1/Task.v1_4_0.yaml#/components/schemas/Task
          description: Accepted; a Task has been generated
        '204':
          description: Success, but no response data
        default:
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RedfishError'
          description: Error condition

11.3.4. OpenAPI file format

With the exception of openapi.yaml, each OpenAPI file contains a YAML object to describe Resources, Resource Collections, or other definitions for the data model. The following terms can be found in the YAML object:

11.3.5. OpenAPI components body

This clause describes the types of definitions that can be found in the components term of a Redfish OpenAPI file.

11.3.5.1. Resource definitions in OpenAPI

To satisfy versioning requirements, the OpenAPI representation of each Resource has one unversioned schema file, and a set of versioned schema files.

The unversioned definition of a Resource contains an anyOf statement. This statement consists of an array of $ref terms, which point to the following:

Example unversioned Resource definition in OpenAPI:

    ComputerSystem:
      anyOf:
      - $ref: http://redfish.dmtf.org/schemas/v1/odata.v4_0_3.yaml#/components/schemas/idRef
      - $ref: http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_0_0.yaml#/components/schemas/ComputerSystem
      - $ref: http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_0_1.yaml#/components/schemas/ComputerSystem
      - $ref: http://redfish.dmtf.org/schemas/v1/ComputerSystem.v1_6_0.yaml#/components/schemas/ComputerSystem
      description: The ComputerSystem schema represents a general purpose machine
        or system.
      x-longDescription: This resource shall be used to represent resources that represent
        a computing system.

The versioned definition of a Resource contains the property definitions for the given version of the Resource.

11.3.5.2. Enumerations in OpenAPI

Definitions for enumerations can consist of the following terms:

Example enumeration definition in OpenAPI:

    IndicatorLED:
      enum:
      - Lit
      - Blinking
      - 'Off'
      type: string
      x-enumDescriptions:
        Blinking: The Indicator LED is blinking.
        Lit: The Indicator LED is lit.
        'Off': The Indicator LED is off.
      x-enumLongDescriptions:
        Blinking: This value shall represent the Indicator LED is in a blinking state
          where the LED is being turned on and off in repetition.
        Lit: This value shall represent the Indicator LED is in a solid on state.
        'Off': This value shall represent the Indicator LED is in a solid off state.
11.3.5.3. Actions in OpenAPI

Versioned definitions of Resources contain a definition called Actions. This definition is a container with a set of terms that point to the different actions supported by the resource.

Example Actions definition:

    Actions:
      additionalProperties: false
      description: The available actions for this resource.
      properties:
        '#ComputerSystem.Reset':
          $ref: '#/components/schemas/Reset'
      type: object
      x-longDescription: This type shall contain the available actions for this resource.

Another definition within the same schema file is used to describe the action itself. This definition contains property definitions for the target and title properties shown in service response payloads for the Resource.

Example definition of an action:

    Reset:
      additionalProperties: false
      description: This action is used to reset the system.
      properties:
        target:
          description: Link to invoke action
          format: uri
          type: string
        title:
          description: Friendly action name
          type: string
      type: object
      x-longDescription: This action shall perform a reset of the ComputerSystem.

The parameters for the action are shown in another definition with RequestBody appended to the name of the action. This gets mapped from the openapi.yaml file for expressing the POST method for the URI of the action.

Example definition of parameters of an action:

    ResetRequestBody:
      additionalProperties: false
      description: This action is used to reset the system.
      properties:
        ResetType:
          $ref: http://redfish.dmtf.org/schemas/v1/Resource.yaml#/components/schemas/ResetType
          description: The type of reset to be performed.
          x-longDescription: This parameter shall define the type of reset to be performed.
      type: object
      x-longDescription: This action shall perform a reset of the ComputerSystem.

11.3.6. OpenAPI terms used by Redfish

The following OpenAPI terms are used to provide schema annotations for Redfish OpenAPI files:

11.4. Schema modification rules

Schema referenced from the implementation may vary from the canonical definitions of those schema defined by the Redfish Schema or other entities, provided they adhere to the rules in the list below. Clients should take this into consideration when attempting operations on the resources defined by schema.

12. Service details

12.1. Eventing

This clause covers the REST-based mechanism for subscribing to and receiving event messages.

NOTE: Refer to the Security details clause for security implications of Eventing.

12.1.1. Event subscription types

The Redfish Service requires a client or administrator to create subscriptions to receive events. There are two methods of creating a subscription: directly by sending an HTTP POST to the subscription collection, or indirectly when a Server-Sent Events (SSE) connection is opened for the Event Service.

12.1.1.1. POST to the subscription collection method

The client locates the Event Service by traversing the Redfish Service interface. The Event Service is found off of the Service Root as described in the Redfish Schema for that service.

When the service has been discovered, clients subscribe to messages by sending a HTTP POST to the URI of the Resource Collection for "Subscriptions" in the Event Service. This request includes the URI where an event-receiver client expects events to be sent, as well as the type of events to be sent. The Redfish Service will then, when an event is triggered within the service, send an event to that URI. The specific syntax of the subscription body is found in the Redfish Schema definition for "EventDestination".

On success, the Event Service shall return an HTTP status 201 (CREATED) and the Location header in the response shall contain a URI giving the location of the newly created subscription resource. The body of the response, if any, shall contain a representation of the subscription resource conforming to the "EventDestination" schema. Sending an HTTP GET to the subscription resource shall return the configuration of the subscription. Clients begin receiving events after a subscription has been registered with the service and do not receive events retroactively. Historical events are not retained by the service.

To unsubscribe from the messages associated with this subscription, the client or administrator simply sends an HTTP DELETE request to the subscription resource URI.

These are some configurable properties that are global settings that define the behavior for all event subscriptions. See the properties defined in the "EventService" Redfish Schema for details of the parameters available to configure the service's behavior.

12.1.1.2. SSE method

A service may support the "ServerSentEventUri" property within the Event Service resource. If a client performs a GET on the URI specified by the "ServerSentEventUri", an SSE connection will be opened for the client. See the Server-Sent Events: EventService section for details on this method.

12.1.2. EventType based eventing

There are three types of events generated in a Redfish Service - life cycle, alert, and metric report. This method of eventing has been deprecated in the Redfish Schema.

Life cycle events happen when resources are created, modified or destroyed. Not every modification of a resource will result in an event - this is similar to when ETags are changed and implementations may not send an event for every resource change. For instance, if an event was sent for every Ethernet packet received or every time a sensor changed 1 degree, this could result in more events than fits a scalable interface. This event usually indicates the resource that changed as well as, optionally, any properties that changed.

Alert events happen when a resource needs to indicate an event of some significance. This may be either directly or indirectly pertaining to the resource. This style of event usually adopts a message registry approach similar to extended error handling in that a MessageId will be included. Examples of this kind of event are when a chassis is opened, button is pushed, cable is unplugged or threshold exceeded. These events usually do not correspond well to life cycle type events hence they have their own category.

Metric report events happen when the TelemetryService has generated a new Metric Report or updated an existing Metric Report. These types of events shall be generated as specified by the MetricReportDefinition resources found subordinate to the TelemetryService. This can be defined to be done on a periodic basis, on demand, or when changes in the metric properties are detected. See the Redfish MetricReportDefinition Schema for full details.

12.1.3. Ways to register for events

Event subscriptions can be subscribed to by specifying a RegistryPrefixes, ResourceTypes, OriginResources (including SubordinateResources) property to filter events to any EventDestination. An EventFormatType can also be specified.

The RegistryPrefixes property has the list of message registries that the service provides and that the subscriber would like messages corresponding to. The values of this property are the values of the RegistryPrefix and can be standard or OEM message registries. It acts like a filter, only sending messages to the subscriber if the RegistryPrefix in the subscription matches the RegistryPrefix of the registry. This value does not include the version of the registry. If this value is empty when subscribing, the subscriber can receive messages from any registry.

The ResourceTypes property has the list of Resource Types that the service provides events on which the subscriber can use in the ResourceType property of the EventDestination. The values of this property is an array of Resource Types and can be standard or OEM schema Resource Types. It acts like a filter, only sending messages to the subscriber if the ResourceType in the subscription matches the Resource Type of the OriginOfCondition. This value does not include the version of the schema (thus there are no periods). For example, if the normal Resource Type is "Task.v1_2_0.Task", then the value in this property is just "Task". If this value is empty when subscribing, the subscriber can receive messages from any resource.

OriginResources can be specified to limit the events sent to the destination to the resource list (in URI format) specified. Leaving this property empty indicates that events from any resources are acceptable. The property SubordinateResources can be specified to indicate those resources as well as subordinate ones, regardless of depth.

EventFormatType can be specified in the subscription as well. The service advertises the list of formats that can be sent using the EventFormatTypes property in the EventService. This value represents the format of the payload sent to the Event Destination. If the value is not specified, then the payload will correspond to the Event Schema.

12.1.4. Event formats

There are two formats of events:

12.1.4.1. Event message objects

Event message objects POSTed to the specified client endpoint shall contain the properties as described in the Redfish Event Schema.

This event message structure supports a message registry. In a message registry approach, there is a message registry that has a list or array of MessageIds in a well-known format. These MessageIds are terse in nature and thus they are much smaller than actual messages, making them suitable for embedded environments. In the registry, there is also a message. The message itself can have arguments as well as default values for Severity and RecommendedActions.

The MessageId property contents shall be of the form:

RegistryName.MajorVersion.MinorVersion.MessageKey

where

Event messages may also have an EventGroupId property. The purpose of this property is to let clients know that different messages may be from the same event. For instance, if a LAN cable is disconnected, they may get a specific message from one registry about the LAN cable being disconnected, another message from a general registry about the resource changing, perhaps a message about resource state change and maybe even more. In order for the client to be able to tell all of these have the same root cause, these messages would have the same value for the EventGroupId property.

12.1.4.2. Metric report message objects

Metric report message objects sent to the specified client endpoint shall contain the properties as described in the Redfish MetricReport Schema.

12.1.5. OEM Extensions

OEMs can extend both messages and message registries. There are OEM sections defined in any individual message (per the message registry schema definition). Thus if OEMs want to provide additional information or properties, this can be done using the OEM section. OEMs shall not supply additional message arguments beyond those in a standard message registry. OEMs may substitute their own message registry for the standard registry to provide the OEM section within the registry but shall not change the standard values (such as Messages) in such registries.

12.2. Asynchronous operations

Services that support asynchronous operations will implement the Task service and Task resource.

The Task service is used to describe the service that handles tasks. It contains a Resource Collection of zero or more "Task" resources. The Task resource is used to describe a long-running operation that is spawned when a request will take longer than a few seconds, such as when a service is instantiated. Clients will poll the URI of the Task resource to determine when the operation has been completed and if it was successful.

The Task structure in the Redfish Schema contains the exact structure of a Task. The type of information it contains are start time, end time, task state, task status, and zero or more messages associated with the task.

Each task has a number of possible states. The exact states and their semantics are defined in the Task resource of the Redfish Schema.

When a client issues a request for a long-running operation, the service returns a status of 202 (Accepted).

Any response with a status code of 202 (Accepted) shall include a location header containing the URL of the Task Monitor and may include the Retry-After header to specify the amount of time the client should wait before querying status of the operation.

The Task Monitor is an opaque URL generated by the service intended to be used by the client that initiated the request. The client queries the status of the operation by performing a GET request on the Task Monitor.

The client should not include the mime type application/http in the Accept Header when performing a GET request to the Task Monitor.

The response body of a 202 (Accepted) should contain an instance of the Task resource describing the state of the task.

As long as the operation is in process, the service shall continue to return a status code of 202 (Accepted) when querying the Task Monitor returned in the location header. If a service supports canceling a task, it shall have DELETE in the Allow header for the Task Monitor.

The client may cancel the operation by performing a DELETE on the Task Monitor URL. The service determines when to delete the associated Task resource object.

The client may also cancel the operation by performing a DELETE on the Task resource. Deleting the Task resource object may invalidate the associated Task Monitor and subsequent GET on the Task Monitor URL returns either 410 (Gone) or 404 (Not Found).

In the unlikely event that a 202 (Accepted) is returned on the DELETE of the Task Monitor or Task resource, an additional Task shall not be started and instead the existing Task resource may be monitored for status of the cancellation request. When the Task has finally completed cancellation, operations to the Task Monitor and Task resource shall return a 404 (Not Found).

After the operation has been completed, the service shall update the TaskState with the appropriate value. The values indicating that a task has been completed are defined in the Task schema.

After the operation has been completed, the Task Monitor shall return the appropriate status code (such as, but not limited to, OK 200 for most operations, Created 201 for POST to create a resource) and include the headers and response body of the initial operation, as if it had been completed synchronously. If the initial operation resulted in an error, the body of the response shall contain an Error Response.

The service may return a status code of 410 (Gone) or 404 (Not Found) if the operation has been completed and the service has already deleted the task. This can occur if the client waits too long to read the Task Monitor.

The client can continue to get information about the status by directly querying the Task resource using the Resource identifier returned in the body of the 202 (Accepted) response.

12.3. Resource Tree stability

The Resource Tree, which is defined as the set of URIs and array elements within the implementation, should be consistent on a single service across device reboot and A/C power cycle, and should withstand a reasonable amount of configuration change (e.g., adding an adapter to a server). The Resource Tree on one service may not be consistent across instances of devices. The client should walk the data model and discover resources to interact with them. It is possible that some resources will remain very stable from system to system (e.g., BMC network settings) -- but it is not an architectural guarantee.

12.4. Discovery

Automatic discovery of managed devices supporting the Redfish Scalable Platform Management API may be accomplished using the Simple Service Discovery Protocol (SSDP). This protocol allows for network-efficient discovery without resorting to ping-sweeps, router table searches, or restrictive DNS naming schemes. Use of SSDP is optional, and if implemented, shall allow the user to disable the protocol through the 'Manager Network Service' resource.

As the objective of discovery is for client software to locate Redfish-compliant managed devices, the primary SSDP functionality incorporated is the M-SEARCH query. Redfish also follows the SSDP extensions and naming used by UPnP where applicable, such that Redfish-compliant systems can also implement UPnP without conflict.

12.4.1. UPnP compatibility

For compatibility with general purpose SSDP client software, primarily UPnP, UDP port 1900 should be used for all SSDP traffic. In addition, the Time-to-Live (TTL) hop count setting for SSDP multicast messages should default to 2.

12.4.2. USN format

The UUID supplied in the USN field of the service shall equal the UUID property of the service root. If there are multiple/redundant managers, the UUID of the service shall remain static regardless of redundancy failover. The Unique ID shall be in the canonical UUID format, followed by '::dmtf-org'

12.4.3. M-SEARCH response

The Redfish Service Search Target (ST) is defined as: urn:dmtf-org:service:redfish-rest:1

The managed device shall respond to M-SEARCH queries searching for Search Target (ST) of the Redfish Service as well as "ssdp:all". For UPnP compatibility, the managed device should respond to M-SEARCH queries searching for Search Target (ST) of "upnp:rootdevice".

The URN provided in the ST header in the reply shall use a service name of "redfish-rest:" followed by the major version of the Redfish specification. If the minor version of the Redfish Specification to which the service conforms is a non-zero value, and that version is backward-compatible with previous minor revisions, then that minor version shall be appended and preceded with a colon. For example, a service conforming to a Redfish specification version "1.4" would reply with a service of "redfish-rest:1:4".

The managed device shall provide clients with the AL header pointing to the Redfish Service Root URL.

For UPnP compatibility, the managed device should provide clients with the LOCATION header pointing to the UPnP XML descriptor.

An example response to an M-SEARCH multicast or unicast query shall follow the format shown below. A service may provide additional headers for UPnP compatibility. Fields in brackets are placeholders for device-specific values.

HTTP/1.1 200 OK
CACHE-CONTROL:max-age=<seconds, at least 1800>
ST:urn:dmtf-org:service:redfish-rest:1
USN:uuid:<UUID of Manager>::urn:dmtf-org:service:redfish-rest:1
AL:<URL of Redfish Service root>
EXT:

12.4.4. Notify, alive, and shutdown messages

Redfish devices may implement the additional SSDP messages defined by UPnP to announce their availability to software. This capability, if implemented, shall allow the end user to disable the traffic separately from the M-SEARCH response functionality. This allows users to utilize the discovery functionality with minimal amounts of network traffic generated.

12.5. Server-Sent Events

Server-Sent Events (SSE), as defined by the Web Hypertext Application Technology Working Group, allows for a client to open a connection with a web service, and the web service can continuously push data to the client as needed. Resource responses for SSE shall have a Content-Type header set as "text/event-stream;charset=UTF-8". A service may occasionally send a comment within a stream to keep the connection alive. The following clauses describe how this is used by Redfish in different contexts of the Redfish data model. Details about SSE can be found in the HTML5 Specification.

12.5.1. EventService

A service's implementation of the "EventService" resource may contain a property called "ServerSentEventUri". If a client performs a GET on the URI specified by the "ServerSentEventUri", the service shall keep the connection open and conform to the HTML5 Specification until the client closes the socket. Events generated by the service shall be sent to the client using the open connection.

When a client opens an SSE stream for the EventService, the service shall create an EventDestination instance in the Subscriptions collection for the EventService to represent the connection. The "Context" property in the EventDestination resource shall be an opaque string generated by the service. The service shall delete the corresponding EventDestination instance when the connection is closed. The service shall close the connection if the corresponding EventDestination is deleted.

There are two formats of SSE streams:

The service should support using the $filter query parameter provided in the URI for the SSE stream by the client to reduce the amount of data returned to the client. The following table shows the properties that the service should allow to be filtered. The $filter syntax shall follow the format specified in the Query parameters for Filter clause.

Property Description Example
EventType The service shall only send Events of the matching EventType. See the EventType enum defined by the Redfish Event Schema for the values allowed. http://sseuri?$filter=EventType eq StatusChange
MetricReportDefinition The service shall only send MetricReports generated from the specified MetricReportDefinition. http://sseuri?$filter=MetricReportDefinition eq '/redfish/v1/TelemetryService/MetricReportDefinitions/PowerMetrics'
RegistryPrefix The service shall only send Events with Messages that are part of the specified Registry Prefix. http://sseuri?$filter=(RegistryPrefix eq Resource) or (RegistryPrefix eq Task)
ResourceType The service shall only send Events for resources matching the type. http://sseuri?$filter=(ResourceType eq 'Power') or (ResourceType eq 'Thermal')
EventFormatType The service shall only send event payloads of the matching type. See the EventFormatType enum defined by the Redfish EventService Schema for the values allowed. http://sseuri?$filter=EventFormatType eq Event
MessageId The service shall only send Events containing the matching Message Id. http://sseuri?$filter=MessageId eq 'Contoso.1.0.TempAssert'
OriginResource The service shall only send Events for the specified resource. http://sseuri?$filter=OriginResource eq '/redfish/v1/Chassis/1/Thermal'
12.5.1.1. Event message SSE stream

The service shall use the "id" field in the SSE stream to uniquely indicate an event. The value of the "id" field shall be the same as the "Id" property in the event payload. The value of the "Id" property should be a positive integer value and should be generated in a sequential manner. A service should accept the "Last-Event-ID" header from the client to allow a client to restart the event stream in case the connection is interrupted.

The service shall use the "data" field in the SSE stream to include the JSON representation of the Event object as defined in the Event message objects section.

The example payload below shows a stream containing a single event with the "id" field set to 1, and the "data" field containing a single Event object.

id: 1
data:{
data:    "@odata.type": "#Event.v1_1_0.Event",
data:    "Id": "1",
data:    "Name": "Event Array",
data:    "Context": "ABCDEFGH",
data:    "Events": [
data:        {
data:            "MemberId": "1",
data:            "EventType": "Alert",
data:            "EventId": "ABC132489713478812346",
data:            "Severity": "Warning",
data:            "EventTimestamp": "2017-11-23T17:17:42-0600",
data:            "Message": "The LAN has been disconnected",
data:            "MessageId": "Alert.1.0.LanDisconnect",
data:            "MessageArgs": [
data:                "EthernetInterface 1",
data:                "/redfish/v1/Systems/1"
data:            ],
data:            "OriginOfCondition": {
data:                "@odata.id": "/redfish/v1/Systems/1/EthernetInterfaces/1"
data:            },
data:            "Context": "ABCDEFGH"
data:        }
data:    ]
data:}
12.5.1.2. Metric report SSE stream

The service shall use the "id" field in the SSE stream to uniquely indicate a metric report transmission. The value of the "id" field shall be the same as the "ReportSequence" property in the metric report payload. The value of the "ReportSequence" property should be a positive integer value and should be generated in a sequential manner. A service should accept the "Last-Event-ID" header from the client to allow a client to restart the metric report stream in case the connection is interrupted.

The service shall use the "data" field in the SSE stream to include the JSON representation of the Metric Report object as defined in the Metric report message objects section.

The example payload below shows a stream containing a metric report with the "id" field set to 127, and the "data" field containing the Metric Report object.

id: 127
data:{
data:    "@odata.id": "/redfish/v1/TelemetryService/MetricReports/AvgPlatformPowerUsage",
data:    "@odata.type": "#MetricReport.v1_0_0.MetricReport",
data:    "Id": "AvgPlatformPowerUsage",
data:    "Name": "Average Platform Power Usage metric report",
data:    "ReportSequence": "127",
data:    "MetricReportDefinition": {
data:        "@odata.id": "/redfish/v1/TelemetryService/MetricReportDefinitions/AvgPlatformPowerUsage"
data:    },
data:    "MetricValues": [
data:        {
data:            "MetricId": "AverageConsumedWatts",
data:            "MetricValue": "100",
data:            "Timestamp": "2016-11-08T12:25:00-05:00",
data:            "MetricProperty": "/redfish/v1/Chassis/Tray_1/Power#/0/PowerConsumedWatts"
data:        },
data:        {
data:            "MetricId": "AverageConsumedWatts",
data:            "MetricValue": "94",
data:            "Timestamp": "2016-11-08T13:25:00-05:00",
data:            "MetricProperty": "/redfish/v1/Chassis/Tray_1/Power#/0/PowerConsumedWatts"
data:        },
data:        {
data:            "MetricId": "AverageConsumedWatts",
data:            "MetricValue": "100",
data:            "Timestamp": "2016-11-08T14:25:00-05:00",
data:            "MetricProperty": "/redfish/v1/Chassis/Tray_1/Power#/0/PowerConsumedWatts"
data:        }
data:    ]
data:}

13. Security details

13.1. Protocols

13.1.1. TLS

Implementations shall support TLS v1.1 or later.

Implementations should support the latest version of the TLS v1.x specification.

Implementations should support the SNIA TLS Specification for Storage Systems.

13.1.2. Cipher suites

Implementations should support AES-256 based ciphers from the TLS suites.

Redfish implementations should consider supporting ciphers similar to below that enable authentication and identification without use of trusted certificates.

     TLS_PSK_WITH_AES_256_GCM_SHA384
 TLS_DHE_PSK_WITH_AES_256_GCM_SHA384
 TLS_RSA_PSK_WITH_AES_256_GCM_SHA384

Additional advantage with using above recommended ciphers is:

"AES-GCM is not only efficient and secure, but hardware implementations can achieve high speeds with low cost and low latency, because the mode can be pipelined."

Redfish implementations should support the following additional ciphers.

        TLS_RSA_WITH_AES_128_CBC_SHA

References to RFCs:

 http://tools.ietf.org/html/rfc5487
 http://tools.ietf.org/html/rfc5288

13.1.3. Certificates

Redfish implementations shall support replacement of the default certificate if one is provided.

Redfish implementations shall use certificates that are compliant with X.509 v3 certificate format, as defined in RFC5280.

13.2. Authentication

13.2.1. HTTP header security

13.2.1.1. HTTP redirect

13.2.2. Extended error handling

13.2.3. HTTP header authentication

13.2.3.1. BASIC authentication

HTTP BASIC authentication as defined by RFC7235 shall be supported, and shall only use compliant TLS connections to transport the data between any third-party authentication service and clients.

13.2.3.2. Request/Message level authentication

Every request that establishes a secure channel shall be accompanied by an authentication header.

13.2.4. Session management

13.2.4.1. Session life cycle management

Session management is left to the implementation of the Redfish Service. This includes orphaned session timeout and the number of simultaneous open sessions.

13.2.4.2. Redfish login sessions

For functionality requiring multiple Redfish operations, or for security reasons, a client may create a Redfish Login Session via the session management interface. The URI used for session management is specified in the Session Service. The URI for establishing a session can be found in the SessionService's Session property or in the Service Root's Links Property under the Sessions property. Both URIs shall be the same.

{
    "SessionService": {
        "@odata.id": "/redfish/v1/SessionService"
    },
    "Links": {
        "Sessions": {
            "@odata.id": "/redfish/v1/SessionService/Sessions"
        }
    },
    ...
}
13.2.4.3. Session login

A Redfish session is created, without requiring an authentication header, by an HTTP POST to the SessionService's Sessions Resource Collection, including the following POST body:

POST /redfish/v1/SessionService/Sessions HTTP/1.1
Host: <host-path>
Content-Type: application/json;charset=utf-8
Content-Length: <computed-length>
Accept: application/json;charset=utf-8
OData-Version: 4.0

{
    "UserName": "<username>",
    "Password": "<password>"
}

The Origin header should be saved in reference to this session creation and compared to subsequent requests using this session to verify the request has been initiated from an authorized client domain.

The response to the POST request to create a session shall include the following:

Location: /redfish/v1/SessionService/Sessions/1
X-Auth-Token: <session-auth-token>

{
    "@odata.id": "/redfish/v1/SessionService/Sessions/1",
    "@odata.type": "#Session.v1_0_0.Session",
    "Id": "1",
    "Name": "User Session",
    "Description": "User Session",
    "UserName": "<username>"
}

The client sending the session login request should save the "session auth token" and the hyperlink returned in the Location header. The "session auth token" is used to authentication subsequent requests by setting the Request Header "X-Auth-Token with the "session auth token" received from the login POST. The client will later use the hyperlink that was returned in the Location header of the POST to log out or terminate the session.

Note that the "session ID" and "session auth token" are different. The session ID uniquely identifies the session resource and is returned with the response data as well as the last segment of the Location header hyperlink. An administrator with sufficient privilege can view active sessions and also terminate any session using the associated 'sessionId'. Only the client that executes the login will have the session auth token.

13.2.4.4. X-Auth-Token HTTP header

Implementations shall only use compliant TLS connections to transport the data between any third-party authentication service and clients. Therefore, the POST to create a new session shall only be supported with HTTPS, and all requests that use Basic Auth shall require HTTPS. A request via POST to create a new session using the HTTP port should redirect to the HTTPS port if both HTTP and HTTPS are enabled.

13.2.4.5. Session lifetime

Note that Redfish sessions "time-out" as opposed to having a token expiration time like some token-based methods use. For Redfish sessions, as long as a client continues to send requests for the session more often than the session timeout period, the session will remain open and the session auth token remains valid. If the sessions times out, the session is automatically terminated.

13.2.4.6. Session termination or logout

A Redfish session is terminated when the client logs out. This is accomplished by performing a DELETE to the Session resource identified by the hyperlink returned in the Location header when the session was created, or the 'sessionId' returned in the response data.

The ability to DELETE a Session by specifying the Session resource ID allows an administrator with sufficient privilege to terminate other users' sessions from a different session.

When a session is terminated, the service shall not affect independent connections established originally by this session for other purposes, such as connections for Server-Sent Events or transferring an image for the Update Service.

13.2.5. AccountService

13.2.6. Password management

A Redfish Service provides local user accounts via a collection of ManagerAccount resources located under the AccountService. The ManagerAccount resources allow users to manage their own account information, and for administrators to create, delete, and manage other user accounts.

13.2.6.1. Password change required handling

The Service may require that passwords assigned by the manufacturer be changed by the end user prior to accessing the Service. In addition, administrators may require users to change their account's password upon first access.

The ManagerAccount resource contains a PasswordChangeRequired boolean property to enable this functionality. Resources that have the property set to True shall require the user to change the write-only Password property in that resource before access is granted. Manufacturers including user credentials for the Service may use this method to force a change to those credentials before access is granted.

When a client accesses the Service using credentials from a ManagerAccount resource that has a PasswordChangeRequired value of True, the Service shall:

13.2.7. Async tasks

13.2.8. Event subscriptions

13.2.9. Privilege model/Authorization

The Authorization subsystem uses Roles and Privileges to control which users have what access to resources.

13.2.10. Redfish Service operation-to-privilege mapping

For every request made by a Redfish client to a Redfish Service, the Redfish Service shall determine that the authenticated identity of the requester has the authorization to perform the requested operation on the resource specified in the request. Using the role and privileges authorization model, where an authenticated identity context is assigned a role and a role is a set of privileges, the service will typically check a HTTP request against a mapping of the authenticated requesting identity role/privileges and determine whether the identity privileges are sufficient to perform the operation specified in the request.

13.2.10.1. Why specify operation-to-privilege mapping

Initial versions of the Redfish specifications specified several Role-to-Privilege mappings for standardized Roles and normatively identified several Privilege labels but did not normatively define what these privileges meant in detail or how operations-to-privilege mappings could be specified or represented in a normative fashion. The lack of a methodology to define what privilege(s) are required to perform a specific requested operation against the URI specified in the request puts at risk the interoperability between Redfish Service implementations that Redfish clients may encounter due to variances in privilege requirements between implementations. Also, a lack of methodology for specifying and representing the operation-to-privilege mapping prevents the Redfish Forum or other governing organizations to normatively define privilege requirements for a service.

13.2.10.2. Representing operation-to-privilege mappings

A Redfish Service should provide a Privilege Registry file in the service Registry Collection. The Privilege Registry file represents the Privilege(s) required to perform an operation against a URI specified in a HTTP request to the service. The Privilege Registry is a single JSON document that contains a Mappings array of PrivilegeMapping entity elements where there is an individual element for every schema entity supported by the service. The operation-to-privilege mapping is defined for every entity schema and applies to every resource the service implements for the applicable schema. There are several situations where specific resources or elements of resources may have differing operation-to-privilege mappings than the entity mappings and the entity level mappings have to be overridden. The methodology for specifying entity level operation-to-privilege mappings and related overrides are defined in the PrivilegeRegistry schema.

If a Redfish Service provides a Privilege Registry document, the service shall use the Redfish Forum's Redfish Privilege Mapping Registry definition as a base operation-to-privilege mapping definition for operations that the service supports to promote interoperability for Redfish clients.

13.2.10.3. OperationMap syntax

An operation map defines the set of privileges required to perform a specific operation on an entity, entity element, or resource. The operations mapped are GET, PUT, PATCH, POST, DELETE and HEAD. Privilege mapping are defined for each operation irrespective of whether the service or the API data model support the specific operation on the entity, entity element, or resource. Privilege labels used may be the Redfish standardized labels defined in the Privilege.PrivilegeType enumeration and they may be OEM-defined privilege labels. The privileges required for an operation can be specified with logical AND and OR behavior as required (see the Privilege AND and OR syntax clause for more information). The following example defines the privileges required for various operations on a Manager entity. Unless mapping overrides to the OperationMap array are defined (syntax explained in next clause), the specified operation-to-privilege mapping would represent behavior for all Manager resources in a service implementation.

{
    "Entity": "Manager",
    "OperationMap": {
        "GET": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "HEAD": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "PATCH": [
            {
                "Privilege": [ "ConfigureManager" ]
            }
        ],
        "POST": [
            {
                "Privilege": [ "ConfigureManager" ]
            }
        ],
        "PUT": [
            {
                "Privilege": [ "ConfigureManager" ]
            }
        ],
        "DELETE": [
            {
                "Privilege": [ "ConfigureManager" ]
            }
        ]
    }
}
13.2.10.4. Mapping overrides syntax

Several situations occur where operation-to-privilege mapping varies from what might be specified at an entity schema level. These situations are:

13.2.10.5. Property override example

In the following example, the Password property on the ManagerAccount resource requires the "ConfigureSelf" or the "ConfigureUsers" privilege to change in contrast to the "ConfigureUsers" privilege required for the rest of the properties on ManagerAccount resources.

{
    "Entity": "ManagerAccount",
    "OperationMap": {
        "GET": [
            {
                "Privilege": [ "ConfigureManager" ]
            },
            {
                "Privilege": [ "ConfigureUsers" ]
            },
            {
                "Privilege": [ "ConfigureSelf" ]
            }
        ],
        "HEAD": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "PATCH": [
            {
                "Privilege": [ "ConfigureUsers" ]
            }
        ],
        "POST": [
            {
                "Privilege": [ "ConfigureUsers" ]
            }
        ],
        "PUT": [
            {
                "Privilege": [ "ConfigureUsers" ]
            }
        ],
        "DELETE": [
            {
                "Privilege": [ "ConfigureUsers" ]
            }
        ]
    },
    "PropertyOverrides": [
        {
            "Targets": [ "Password" ],
            "OperationMap": {
                "GET": [
                    {
                        "Privilege": [ "ConfigureManager" ]
                    }
                ],
                "PATCH": [
                    {
                        "Privilege": [ "ConfigureManager" ]
                    },
                    {
                        "Privilege": [ "ConfigureSelf" ]
                    }
                ]
            }
        }
    ]
}
13.2.10.6. Subordinate override

The Targets property within SubordinateOverrides lists a hierarchical representation for when to apply the override. In the following example, the override for an EthernetInterface entity is applied when it is subordinate to an EthernetInterfaceCollection entity, which in turn is subordinate to a Manager entity. If a client were to PATCH an EthernetInterface entity that matches this override condition, it would require the "ConfigureManager" privilege; otherwise, the client would require the "ConfigureComponents" privilege.

{
    "Entity": "EthernetInterface",
    "OperationMap": {
        "GET": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "HEAD": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "PATCH": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "POST": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "PUT": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "DELETE": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ]
    },
    "SubordinateOverrides": [
        {
            "Targets": [
                "Manager",
                "EthernetInterfaceCollection"
            ],
            "OperationMap": {
                "GET": [
                    {
                        "Privilege": [ "Login" ]
                    }
                ],
                "PATCH": [
                    {
                        "Privilege": [ "ConfigureManager" ]
                    }
                ]
            }
        }
    ]
}
13.2.10.7. ResourceURI Override syntax

In the following example, use of the ResourceURI Override syntax for representing operation privilege variations for specific resource URIs is demonstrated. The example specifies both ConfigureComponents and OEMAdminPriv privileges are required to perform a PATCH operation on the two resource URIs listed as Targets. 

{
    "Entity": "ComputerSystem",
    "OperationMap": {
        "GET": [
            {
                "Privilege": [ "Login" ]
            }
        ],
        "HEAD": [
            { 
                "Privilege": [ "Login" ]
            }
        ],
        "PATCH": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "POST": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "PUT": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ],
        "DELETE": [
            {
                "Privilege": [ "ConfigureComponents" ]
            }
        ]
    },
    "ResourceURIOverrides": [
        {
            "Targets": [
                "/redfish/v1/Systems/VM6",
                "/redfish/v1/Systems/Sys1"
            ],
            "OperationMap": {
                "GET": [
                    {
                        "Privilege": [ "Login" ]
                    }
                ],
                "PATCH": [
                    {
                        "Privilege": [ "ConfigureComponents","OEMSysAdminPriv" ]
                    }
                ]
            }
        }
    ]
}
13.2.10.8. Privilege AND and OR syntax

Logical combinations of privileges required to perform an operation on an entity, entity element, or resource are defined by the array placement of the privilege labels in the OperationMap GET, HEAD, PATCH, POST, PUT, DELETE operation element arrays. For OR logical combinations, the privilege label is placed in the operation element array as individual elements. In the following example, either Login or OEMPrivilege1 privileges are required to perform a GET operation.

{
    "GET": [
        {
            "Privilege": [ "Login" ]
        },
        {
            "Privilege": [ "OEMPrivilege1" ]
        }
    ]
}

For logical AND combinations, the privilege label is placed in the Privilege property array within the operation element. In the following example, both ConfigureComponents and OEMSysAdminPriv are required to perform a PATCH operation.

{
    "PATCH": [
        {
            "Privilege": [ "ConfigureComponents","OEMSysAdminPriv" ]
        }
    ]
}

14. Redfish Host Interface

The Redfish Host Interface Specification defines how software executing on a host computer system can interface with a Redfish Service that manages the host. See DSP0270 for details.

15. Redfish Composability

A service may implement the CompositionService resource off of ServiceRoot to support the binding of resources together. One example is disaggregated hardware, which allows for independent components, such as processors, memory, I/O controllers, and drives, to be bound together to create logical constructs that operate together. This allows for a client to dynamically assign resources for a given application.

A service that supports Composability shall implement the ResourceBlock resource (ResourceBlock schema) and the ResourceZone resource (Zone schema) for the CompositionService. ResourceBlocks provide an inventory of components available to the client for building compositions. ResourceZones describe the binding restrictions of the ResourceBlocks managed by the service.

The ResourceZone resource within the CompositionService shall include the CollectionCapabilities annotation in the response. The CollectionCapabilities annotation allows a client to discover which collections in the service support compositions, the different composition request types allowed, and how the POST request for the collection is formatted, as well as what properties are required.

15.1. Composition requests

A service that implements the CompositionService (as defined by the CompositionService schema) shall support one or more of the following types of composition requests:

A service that supports removing a composed resource shall support the DELETE method on the composed resource.

15.1.1. Specific Composition

A Specific Composition is when a client has identified an exact set of resources in which to build a logical entity. A service that supports Specific Compositions shall support a POST request that contains an array of hyperlinks to ResourceBlocks. The specific nesting of the ResourceBlock array is defined by the schema for the resource being composed.

Example Specific Composition of a ComputerSystem:

POST /redfish/v1/Systems HTTP/1.1
Content-Type: application/json;charset=utf-8
Content-Length: <computed length>
OData-Version: 4.0

{
    "Name": "Sample Composed System",
    "Links": {
        "ResourceBlocks": [
            { "@odata.id": "/redfish/v1/CompositionService/ResourceBlocks/ComputeBlock0" },
            { "@odata.id": "/redfish/v1/CompositionService/ResourceBlocks/DriveBlock2" },
            { "@odata.id": "/redfish/v1/CompositionService/ResourceBlocks/NetBlock4" }
        ]
    }
}

15.1.2. Constrained Composition

A Constrained Composition is when a client has identified a set of criteria (or constraints) in which to build a logical entity. This includes criteria such as quantities of components, or characteristics of components. A service that supports Constrained Compositions shall support a POST request that contains the set of characteristics to apply to the composed resource. The specific format of the request is defined by the schema for the resource being composed. This type of request may include expanded elements of resources subordinate to the composed resource.

Example Constrained Composition of a ComputerSystem:

POST /redfish/v1/Systems HTTP/1.1
Content-Type: application/json;charset=utf-8
Content-Length: <computed length>
OData-Version: 4.0

{
    "Name": "Sample Composed System",
    "PowerState": "On",
    "BiosVersion": "P79 v1.00 (09/20/2013)",
    "Processors": {
        "Members": [
            {
                "@Redfish.RequestedCount": 4,
                "@Redfish.AllowOverprovisioning": true,
                "ProcessorType": "CPU",
                "ProcessorArchitecture": "x86",
                "InstructionSet": "x86-64",
                "MaxSpeedMHz": 3700,
                "TotalCores": 8,
                "TotalThreads": 16
            }
        ]
    },
    "Memory": {
        "Members": [
            {
                "@Redfish.RequestedCount": 4,
                "CapacityMiB": 8192,
                "MemoryType": "DRAM",
                "MemoryDeviceType": "DDR4"
            }
        ]
    },
    "SimpleStorage": {
        "Members" : [
            {
                "@Redfish.RequestedCount": 6,
                "Devices": [
                    {
                        "CapacityBytes": 322122547200
                    }
                ]
            }
        ]
    },
    "EthernetInterfaces": {
        "Members": [
            {
                "@Redfish.RequestedCount": 1,
                "SpeedMbps": 1000,
                "FullDuplex": true,
                "NameServers": [
                    "names.redfishspecification.org"
                ],
                "IPv4Addresses": [
                    {
                        "SubnetMask": "255.255.252.0",
                        "AddressOrigin": "Dynamic",
                        "Gateway": "192.168.0.1"
                    }
                ]
            }
        ]
    }
}

15.1.3. Expandable Resources

An Expandable Resource is when a service has a baseline composition that cannot be removed. Instead of a client making requests to create a new composed resource, a client is only allowed to add or remove resources from the composed resource. A service that supports Expandable Resources shall support one or more of the update methods listed in the Updating a Composed Resource clause.

15.2. Updating a Composed Resource

A service that supports updating a composed resource shall provide one or more of the following methods for updating composed resources:

16. ANNEX A (informative)

16.1. Change log

Version Date Description
1.7.0 2019-05-16 The specification has been significantly rewritten for clarity. Except for the additions listed below, no normative changes were made. Any clarifications that inadvertently altered the normative behavior are considered errata, and will be corrected in future revisions to the specification.
Added missing normative statements regarding handling of array properties and PATCH operations on arrays.
Separated data model and schema clauses.
Added missing clauses that describe how JSON Schema and OpenAPI files are formatted.
Added missing clause about the schema versioning methodology.
Added missing clause about how URI patterns are constructed based on the Resource Tree and property hierarchy.
Added Dictionary file naming rules and repository locations.
Enhanced localization definitions and defined repository locations.
Added missing statement about SSE within the "Eventing mechanism" clause.
Added Constrained Composition and Expandable Resources clauses to Redfish Composability.
Added clause about requiring Event Subscriptions to be persistent across service restarts.
Added clause about persistence of Tasks generated as a result of using "@Redfish.OperationApplyTime" across service restarts.
Added clause about using "@Redfish.OperationApplyTime" and "@Redfish.MaintenanceWindow" within Task responses.
Removed "@odata.context" property from example payloads.
Added "Password Management" clause to describe functional behavior for restricting access when an account requires a password change.
Added clause around the usage of HTTP status code 403 when an account requires a password change.
1.6.1 2018-12-13 Added clause about percent encoding being allowed for query parameters.
Changed Expand example to use SoftwareInventory instead of LogEntry.
Added missing clause about the usage of a separator for multiple query parameters.
Fixed '$filter' examples to use '/' instead of '.' for property paths.
Clarified the usage of Messages in a successful Action response; provided an example.
Added clarification about services supporting a subset of HTTP operations on resources specified in schema.
Added clarification about services implementing writable properties as read only.
Added clarification about session termination not affecting connections opened by the session.
Added "Redfish Provider" term definition.
Updated JSON Schema references to point to Draft 7 of the JSON Schema specification.
Added clarifications about scenarios for when a request to add an Event Subscription contains conflicting information and how services respond.
Removed language about ignoring the 'Links' property in PATCH requests.
Clarified usage of ETags to show that a client is not supposed to PATCH '@odata.etag' when attempting to use ETag protection for a resource.
Clarified usage of the 'only' query parameter to show it's not to be combined with '$expand' and not to be used with singular resources.
Clarified the usage of HTTP status codes with Task Monitors.
Various spelling and grammar fixes.
1.6.0 2018-08-23 Added methods of using $filter on the SSE URI for the EventService.
Added support for the OpenAPI Specification v3.0. This allows OpenAPI-conforming software to access Redfish Service implementations.
Added strict definitions for the URI patterns used for Redfish Resources to support OpenAPI. Each URI is now constructed using a combination of fixed, defined path segments and the values of "Id" properties for Resource Collections. Also added restrictions on usage of unsafe characters in URIs. Implementations reporting support for Redfish v1.6.0 conform to these URI patterns.
Added support for creating and naming Redfish schema files in the OpenAPI YAML-based format.
Added URI construction rules for OEM extensions.
Changed ETag usage to require strong ETag format.
Added requirement for HTTP Allow header as a response header for GET and HEAD operations.
Added Metric Reports as a type of event that can be produced by a Redfish Service. Added support for SSE streaming of Metric reports in support of new TelemetryService schema.
Added Registry, Resource, Origin, or EventFormatType-based event subscription methods as detailed in the Specification and schema. Added an EventFormatType to allow for additional payload types for subscription-based or streaming events. Deprecated 'EventType'-based event subscription mechanism.
Added Event message grouping capability.
Provided guidance for defining and using OEM extensions for Messages and Message Registries.
Added 'excerpt' and 'only' query parameters.
Clarified requirements for Resource Collection responses, which includes required properties that were expected, but not listed explicitly in the Specification.
Made inclusion of the '@odata.context' annotation optional.
Removed requirement for clients to include the 'OData-Version' HTTP header in all requests.
1.5.1 2018-08-10 Added clarifications to required properties in structured properties derived from ReferenceableMembers.
Reorganized Eventing section to break out the different subscription methods to differentiate pub-sub from SSE.
Removed statements referencing OData conformance levels.
Clarified terminology to explain usage of absolute versus relative reference throughout.
Clarified client-side HTTP Accept header requirements.
Added evaluation order for supported query parameters and clarified examples.
Clarified handling of annotations in response payloads when used with $select queries.
Clarified service handling of annotations in PATCH requests.
Clarified handling of various PATCH request error conditions.
Clarified ability to create Resource Collection members by POST operations to the Resource Collection or the Members[] array within the resource.
Corrected several examples to show required properties in payload.
Clarified usage of the Link header and values of 'rel=describedBy'.
Clarified that the HTTP status code table only describes Redfish-specific behavior and that unless specified, all other usage follows the definitions within the appropriate RFCs.
Added missing entry for HTTP status code 431.
Added statement that HTTP status code 503 can be used during reboot/reset of a Service to indicate that the service is temporarily unavailable.
Clarified usage of the @odata.type annotation within embedded objects.
Added missing statements about required properties 'Name', 'Id', 'MemberId', and common property 'Description', which have always been shown as required in schema files, but were not mentioned in the Specification.
Added guidance for the value of time/date properties when time is unknown.
Added missing description of the 'title' property in Action requests.
Clarified usage of the '@odata.nextLink' annotation at the end of Resource Collections.
Added additional guidance for naming properties and enumeration values that contain 'OEM' or that include acronyms.
Corrected requirements for Description and LongDescription schema annotations.
Corrected name of 'ConfigureComponents' in Operation-to-Privilege mapping clause.
Various typographical errors and grammatical improvements.
1.5.0 2018-04-05 Added support for Server-Sent Eventing for streaming events to web-based GUIs or other clients.
Added "OperationApplyTime" annotation to provide a mechanism for specifying deterministic behavior for the application of Create, Delete or Action (POST) operations.
1.4.1 2018-04-05 Updated name of the DMTF Forum from 'SPMF' to 'Redfish Forum'.
Changed terminology for consistent usage of 'hyperlink'.
Added example to clarify usage of $select query parameter with $expand, and clarified expected results when using 'AutoExpand'. Corrected order of precedence for $filter parameter options.
Corrected terminology for OEM-defined actions removing 'custom' in favor of OEM, and clarified that the Action 'target' property is always required for an Action, along with its usage.
Corrected location header values for responses to Data modification requests that create a Task (Task resource vs. Task Monitor). Clarified error handling of DELETE operations on Task resources.
Removed references to obsolete and unused 'Privilege' annotation namespace.
Clarified usage of the 'Base.1.0.GeneralError' message in the Base Message Registry.
Added missing durable URIs for Registries and Profiles, clarified intended usage for each folder in the Repository. Added missing file naming conventions for Registries and Profiles, and clarified file naming for Schemas.
Added statement to clarify that additional headers may be added to M-SEARCH responses for SSDP to allow for UPnP compatibility.
Clarified assignment requirements for predefined or custom roles when new Manager Account instances are created, using the 'RoleId' property.
1.4.0 2017-11-17 Added support for optional Query parameters ("$expand", "$filter", and "$select") on requests to allow for more efficient retrieval of resources or properties from a Redfish Service.
Clarified HTTP status and payload responses after successful processing of data modification requests. This includes POST operations for performing Actions, as well as other POST, PATCH, or PUT requests.
Added HTTP status code entries for 428 and 507 to clarify the proper response to certain error conditions. Added reference links to the HTTP status code table throughout.
Updated Abstract to reflect current state of the Specification.
Added reference to RFC 6585 and clarified expected behavior when ETag support is used in conjunction with PUT or PATCH operations.
Added definition for "Property" term and updated text to use term consistently.
Added "Client Requirement" column and information for HTTP headers on requests.
Clarified the usage and expected format of the Context property value.
Added clause detailing how Structured properties can be revised and how to resolve their definitions in schema.
Added more descriptive definition for the Settings resource. Added an example for the "SettingsObject". Added description and example for using the "SettingsApplyTime" annotation.
Added Action example using the ActionInfo resource in addition to the simple AllowableValues example. Updated example to show a proper subset of the available enumerations to reflect a real-world example.
Added statement explaining the updates required to TaskState upon task completion.
1.3.0 2017-08-11 Added support for a Service to optionally reject a PATCH or PUT operation if the If-Match or If-Match-None HTTP header is required by returning the HTTP status code 428.
Added support for a Service to describe when the values in the Settings object for a resource are applied via the "@Redfish.SettingsApplyTime" annotation.
1.2.1 2017-08-10 Clarified wording of the "Oem" object definition.
Clarified wording of the "Partial resource results" section.
Clarified behavior of a Service when receiving a PATCH with an empty JSON object.
Added statement about other uses of the HTTP 503 status code.
Clarified format of URI fragments to conform to RFC6901.
Clarified use of absolute and relative URIs.
Clarified definition of the "target" property as originating from OData.
Clarified distinction between "hyperlinks" and the "Links Property".
Corrected the JSON example of the privilege map.
Clarified format of the "@odata.context" property.
Added clauses about the schema file naming conventions.
Clarified behavior of a Service when receiving a PUT with missing properties.
Clarified valid values in the "Accept" header to include wildcards per RFC7231.
Corrected "ConfigureUser" privilege to be spelled "ConfigureUsers".
Corrected Session Login section to include normative language.
1.2.0 2017-04-14 Added support for the Redfish Composability Service.
Clarified Service handling of the Accept-Encoding header in a request.
Improved consistency and formatting of example requests and responses throughout.
Corrected usage of the "@odata.type" property in response examples.
Clarified usage of the "Required" schema annotation.
Clarified usage of SubordinateOverrides in the Privilege Registry.
1.1.0 2016-12-09 Added Redfish Service Operation to Privilege Mapping clause. This functionality allows a Service to present a resource or even property-level mapping of HTTP operations to account Roles and Privileges.
Added references to the Redfish Host Interface Specification (DSP0270).
1.0.5 2016-12-09 Errata release. Various typographical errors.
Corrected terminology usage of "Collection", "Resource Collection" and "Members" throughout.
Added glossary entries for "Resource Collection" and "Members".
Corrected Certificate requirements to reference definitions and requirements in RFC 5280 and added a normative reference to RFC 5280.
Clarified usage of HTTP POST and PATCH operations.
Clarified usage of HTTP Status codes and Error responses.
1.0.4 2016-08-28 Errata release. Various typographical errors.
Added example of an HTTP Link Header and clarified usage and content.
Added Schema Modification clause describing allowed usage of the Schema files.
Added recommendation to use TLS 1.2 or later, and to follow the SNIA TLS Specification. Added reference to the SNIA TLS Specification. Added additional recommended TLS_RSA_WITH_AES_128_CBC_SHA Cipher suite.
Clarified that the "Id" property of a Role resource matches the Role Name.
1.0.3 2016-06-17 Errata release. Corrected missing Table of Contents and Clause numbering. Corrected URL references to external specifications. Added missing Normative References. Corrected typographical error in ETag example.
Clarified examples for ExtendedInfo to show arrays of Messages.
Clarified that a POST to Session Service to create a new Session does not require authorization headers.
1.0.2 2016-03-31 Errata release. Various typographical errors.
Corrected normative language for M-SEARCH queries and responses.
Corrected Cache-Control and USN format in M-SEARCH responses.
Corrected schema namespace rules to conform to OData namespace requirements (.n.n.n becomes .vn_n_n) and updated examples throughout the document to conform to this format. File naming rules for JSON Schema and CSDL (XML) schemas were also corrected to match this format and to allow for future major (v2) versions to coexist.
Added missing clause detailing the location of the Schema Repository and listing the durable URLs for the repository.
Added definition for the value of the Units annotation, using the definitions from the UCUM specification. Updated examples throughout to use this standardized form.
Modified the naming requirements for Oem Property Naming to avoid future use of colon ':' and period '.' in property names, which can produce invalid or problematic variable names when used in some programming languages or environments. Both separators have been replaced with underscore '_', with colon and period usage now deprecated (but valid).
Removed duplicative or out-of-scope sub-clauses from the Security clause, which made unintended requirements on Redfish Service implementations.
Added missing requirement that property names in Resource Responses match the casing (capitalization) as specified in schema.
Updated normative references to current HTTP RFCs and added clause references throughout the document where applicable.
Clarified ETag header requirements.
Clarified that no authentication is required for accessing the Service Root resource.
Clarified description of Retrieving Collections.
Clarified usage of 'charset=utf-8' in the HTTP Accept and Content-Type headers.
Clarified usage of the 'Allow' HTTP Response Header and added missing table entry for usage of the 'Retry-After' header.
Clarified normative usage of the Type Property and Context Property, explaining the ability to use two URL forms, and corrected the "@odata.context" URL examples throughout.
Corrected inconsistent terminology throughout the Collection Resource Response clause.
Corrected name of normative Resource Members Property ('Members', not 'value').
Clarified that Error Responses may include information about multiple error conditions.
Corrected name of Measures.Unit annotation term as used in examples.
Corrected outdated reference to Core OData specification in Annotation Term examples.
Added missing 'Members' property to the Common Redfish Resource Properties clause.
Clarified terminology and usage of the Task Monitor and related operations in the Asynchronous Operations clause.
Clarified that implementation of the SSDP protocol is optional.
Corrected typographical error in the SSDP USN field's string definition (now '::dmtf-org').
Added missing OPTIONS method to the allowed HTTP Methods list.
Fixed nullablity in example.
1.0.1 2015-09-17 Errata release. Various grammatical corrections.
Clarified normative use of LongDescription in schema files.
Clarified usage of the 'rel-describedby' link header.
Corrected text in example of 'Select List' in OData Context property.
Clarified Accept-Encoding Request header handling.
Deleted duplicative and conflicting statement on returning extended error resources.
Clarified relative URI resolution rules.
Clarified USN format.
1.0.0 2015-08-04 Initial release.