Document Identifier: DSP0266
Date: 2016-12-23
Version: 1.0.5
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 This document is available for public review and comment until superseded.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: 1.0.4
Document Class: Normative
Document Status: Published
Document Language: en-US
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CONTENTS
The Redfish Scalable Platforms Management API ("Redfish") was prepared by the Scalable Platforms Management Forum of the DMTF.
DMTF is a not-for-profit association of industry members dedicated to promoting enterprise and systems management and interoperability. For information about the DMTF, see http://www.dmtf.org.
The DMTF acknowledges the following individuals for their contributions to this document:
The Redfish Scalable Platforms Management API ("Redfish") is a new specification that uses RESTful interface semantics to access data defined in model format to perform out-of-band systems management. It is suitable for a wide range of servers, from stand-alone servers to rack mount and bladed environments but scales equally well for large scale cloud environments.
There are several out-of-band systems management standards (defacto and de jour) available in the industry. They all either vary widely in implementation, were developed for single server embedded environments or have their roots in antiquated software modeling constructs. There is no single industry standard that is simple to use, based on emerging programming standards, embedded friendly and capable of meeting large scale data center & cloud needs.
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.
In this document, some terms have a specific meaning beyond the normal English meaning. Those terms are defined in this clause.
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, Annex H. 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, Annex H 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 5.
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.
The following additional terms are used in this document.
| Term | Definition |
|---|---|
| Baseboard Management Controller | An embedded device or service, typically an independent microprocessor or System-on-Chip with associated firmware, within a Computer System used to perform systems monitoring and management-related tasks, which are commonly performed out-of-band. |
| Collection | See Resource Collection. |
| CRUD | Basic intrinsic operations used by any interface: Create, Read, Update and Delete. |
| Event | A record that corresponds to an individual alert. |
| Managed System | In the context of this specification, a managed system is a system that provides information or status, or is controllable, via a Redfish-defined interface. |
| Member | A Member is a single resource instance contained in a Resource Collection |
| Message | A complete request or response, formatted in HTTP/HTTPS. The protocol, based on REST, is a request/response protocol where every Request should result in a Response. |
| Operation | The HTTP request methods that map generic CRUD operations. These are POST, GET, PUT/PATCH, HEAD and DELETE. |
| OData | The Open Data Protocol, as defined in OData-Protocol. |
| OData Service Document | The name for a resource that provides information about the Service Root. The Service Document provides a standard format for enumerating the resources exposed by the service that enables generic hypermedia-driven OData clients to navigate to the resources of the Redfish Service. |
| Redfish Alert Receiver | The name for the functionality that receives alerts from a Redfish Service. This functionality is typically software running on a remote system that is separate from the managed system. |
| Redfish Client | Name for the functionality that communicates with a Redfish Service and accesses one or more resources or functions of the Service. |
| Redfish Protocol | The set of protocols that are used to discover, connect to, and inter-communicate with a Redfish Service. |
| Redfish Schema | The Schema definitions for Redfish resources. It is defined according to OData Schema representation that can be directly translated to a JSON Schema representation. |
| Redfish Service | Also referred to as the "Service". The set of functionality that implements the protocols, resources, and functions that deliver the interface defined by this specification and its associated behaviors for one or more managed systems. |
| Redfish Service Entry Point | Also referred to as "Service Entry Point". The interface through which a particular instance of a Redfish Service is accessed. A Redfish Service may have more than one Service Entry Point. |
| Request | A message from a Client to a Server. It consists of a request line (which includes the Operation), request headers, an empty line and an optional message body. |
| Resource | A Resource is addressable by a URI and is able to receive and process messages. A Resource can be either an individual entity, or a Collection that acts as a container for several other entities. |
| Resource Collection | A Resource Collection is a Resource that acts as a container of other Resources. The Members of a Resource Collection usually have similar characteristics. The container processes messages sent to the container. The Members of the container process messages sent only to that Member without affecting other Members of the container. |
| Resource Tree | A Resource Tree is a tree structure of JSON encoded resources accessible via a well-known starting URI. A client may discover the resources available on a Redfish Service by following the resource links from the base of the tree. NOTE for Redfish client implementation: Although the resources are a tree, the references between resources may result in graph instead of a tree. Clients traversing the resource tree must contain logic to avoid infinite loops. |
| Response | A message from a Server to a Client in response to a request message. It consists of a status line, response headers, an empty line and an optional message body. |
| Service Root | The term Service Root is used to refer to a particular resource that is directly accessed via the service entry point. This resource 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 | The act of registering a destination for the reception of events. |
The following additional abbreviations are used in this document.
| Term | 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 |
The Redfish Scalable Platforms Management API ("Redfish") is a management standard using a data model representation inside of a hypermedia RESTful interface. Because it is based on REST, Redfish is easier to use and implement than many other solutions. Since it is model oriented, it is capable of expressing the relationships between components in modern systems as well as the semantics of the services and components within them. It is also easily extensible. By using a hypermedia approach to REST, Redfish can express a large variety of systems from multiple vendors. By requiring JSON representation, a wide variety of resources can be created in a denormalized fashion not only to improve scalability, but the payload can be easily interpreted by most programming environments as well as being relatively intuitive for a human examining the data. The model is exposed in terms of an interoperable Redfish Schema, expressed in an OData Schema representation with translations to a JSON Schema representation, with the payload of the messages being expressed in a JSON following OData JSON conventions. The ability to externally host the Redfish Schema definition of the resources in a machine-readable format allows the meta data to be associated with the data without encumbering Redfish Services with the meta data, thus enabling more advanced client scenarios as found in many data center and cloud environments.
The scope of this specification is to define the protocols, data model, and behaviors, as well as other architectural components needed for an inter-operable, cross-vendor, remote and out-of-band capable interface that meets the expectations of Cloud and Web-based IT professionals for scalable platform management. While large scale systems are the primary focus, the specifications are also capable of being used for more traditional system platform management implementations.
The specifications define elements that are mandatory for all Redfish implementations as well as optional elements that can be chosen by system vendor or manufacturer. The specifications also define points at which OEM (system vendor) -specific extensions can be provided by a given implementation.
The specifications set normative requirements for Redfish Services and associated materials, such as Redfish Schema files. In general, the specifications do not set requirements for Redfish clients, but will indicate what a Redfish client should do in order to access and utilize a Redfish Service successfully and effectively.
The specifications do not set requirements that particular hardware or firmware must be used to implement the Redfish interfaces and functions.
There are many objectives and goals of Redfish as an architecture, as a data representation, and of the definition of the protocols that are used to access and interact with a Redfish Service. Redfish seeks to provide specifications that meet the following goals:
The following design tenets and technologies are used to help deliver the previously stated goals and characteristics:
Redfish does not guarantee that client software will never need to be updated. Examples that may require updates include accommodation of new types of systems or their components, data model updates, and so on. System optimization for an application will always require architectural oversight. However, Redfish does attempt to minimize instances of forced upgrades to clients using Schemas, strict versioning and forward compatibility rules and through separation of the protocols from the data model.
Inter-operable does not mean identical. A Redfish client may need to adapt to the optional elements that are provided by different vendors. Implementation and configurations of a particular product from a given vendor can also vary.
For example, Redfish does not enable a client to read a Resource Tree and write it to another Redfish Service. This is not possible as it is a hypermedia API. Only the root object has a well known URI. The resource topology reflects the topology of the system and devices it represents. Consequently, different server or device types will result in differently shaped resource trees, potentially even for identical systems from the same manufacturer.
Additionally, not all Redfish resources are simple read/write resources. Implementations may follow other interaction patterns discussed later. As an example, user credentials or certificates cannot simply be read from one service and transplanted to another. Another example is the use of Setting Data instead of writing to the same resource that was read from.
Lastly, the value of links between resources and other elements can vary across implementations. Clients should not assume that links can be reused across different instantiations of a Redfish Service.
This document defines a RESTful interface. Many service applications are exposed as RESTful interfaces.
There are several reasons to define a RESTful interface:
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 is no interoperability between them.
OData defines a set of common RESTful conventions and markup which, if adopted, provides for interoperability between APIs.
Adopting OData conventions for describing Redfish Schema, URL conventions, and naming and structure of common properties in a JSON payload, not only encapsulate best practices for RESTful APIs but further enables Redfish Services to be consumed by a growing ecosystem of generic client libraries, applications, and tools.
The Redfish model is built for managing systems. All resources are defined in OData Schema representation and translated to JSON Schema representation. OData is an industry standard that encapsulates best practices for RESTful services and provides interoperability across services of different types. JSON is being widely adopted in multiple disciplines and has a large number of tools and programming languages that accelerate development when adopting these approaches.
The protocol operations are specified independently of the data model. The protocols are also versioned independently of the data model. The expectation is that the protocol version changes extremely infrequently, while the data model version is allowed to change as needed. This implies that innovation should happen primarily in the data model, not the protocols. It allows the data model to be extended and changed as needed without requiring the protocols or API version to change. Conversely, separating the protocols from the data model allows for changes to occur in the protocols without causing significant changes to the data model.
Like other hypermedia APIs, Redfish has a single service endpoint URI and all other resources are accessible via opaque URIs referenced from the root. Any resource discovered through links found by accessing the root service or any service or resource referenced using references from the root service will conform to the same versions of the protocols supported by the root service.
While the majority of operations in this architecture are synchronous in nature, some operations can take a long time to execute, 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.
The use of HTTP Response codes enable a client to determine if the operation was completed synchronously or asynchronously. For more information, see the clause on Tasks.
In some situations it is useful for a service to provide messages to clients that fall outside the normal request/response paradigm. These messages, called events, are used by the service to asynchronously notify the client of some significant state change or error condition, usually of a time critical nature.
Only one style of eventing is currently defined by this specification - push style eventing. In push style eventing, when the server 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. All subscriptions are persistent configuration settings.
The clause on Eventing further in this specification discusses the details of the eventing mechanism.
Operations can be divided into two sets: intrinsic and extrinsic. Intrinsic operations, often referred to as CRUD, are mapped to HTTP methods. The protocol also has the ability to support extrinsic operations -- those operations that do not map easily to CRUD. Examples of extrinsic would be items that collectively would be better performed if done as a set (for scalability, ease of interface, server side semantic preservation or similar reasons) or operations that have no natural mapping to CRUD operations. One examples is system reset. It is possible to combine multiple operations into a single action. A system reset could be modeled as an update to state, but semantically the client is actually requesting a state change and not simply changing the value in the state.
In Redfish, these extrinsic operations are called actions and are discussed in detail in different parts of this specification.
The Redfish Schema defines certain standard actions associated with common Redfish resources. For these standard actions, the Redfish Schema contains the normative language on the behavior of the action. OEM extensions are also allowed to the Redfish schema, including defining actions for existing resources.
While the service itself is at a well-known URI, the service host must be discovered. Redfish, like UPnP, uses SSDP for discovery. SSDP is supported in a wide variety of devices, such as printers. It is simple, lightweight, IPv6 capable and suitable for implementation in embedded environments. Redfish is investigating additional service entry point discovery (e.g., DHCP-based) approaches.
For more information, see the clause on Discovery
A wide variety of remote access and redirection services are supported in this architecture. Critical to out-of-band environments are mechanisms to support Serial Console access, Keyboard Video and Mouse re-direction (KVM-IP), Command Shell (i.e., Command Line interface) and remote Virtual Media. Support for Serial Console, Command Shell, KVM-IP and Virtual Media are all encompassed in this standard and are expressed in the Redfish Schema. This standard does not define the protocols or access mechanisms for accessing those devices and services. The Redfish Schema provides for the representation and configuration of those services, establishment of connections to enable those services and the operational status of those services. However, the specification of the protocols themselves are outside the scope of this specification.
The challenge with security in a remote interface that is programmatic is to ensure both the interfaces used to interact with Redfish and the data being exchanged are secured. This means designing the proper security control mechanisms around the interfaces and securing the channels used to exchange the data. As part of this, specific behaviors are to be put in place including defining and using minimum levels of encryption for communication channels etc.
The Redfish Scalable Platform Management API is based on REST and follows OData conventions for interoperability, as defined in OData-Protocol, JSON payloads, as defined in OData-JSON, and a machine-readable representation of schema, as defined in OData-Schema. The OData Schema representations include annotations to enable direct translation to JSON Schema representations for validation and consumption by tools supporting JSON Schema. Following these common standards and conventions increases interoperability and enables leveraging of existing tool chains.
Redfish follows the OData minimal conformance level for clients consuming minimal metadata.
Throughout this document, we refer to Redfish as having a protocol mapped to a data model. More accurately, 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. For simplicity though, we will refer to the RESTful mapping to HTTP, TCP/IP and other protocol, transport and messaging layer aspects as the Redfish protocol.
The Redfish protocol is designed around a web service based interface model, and designed for network and interaction efficiency for both user interface (UI) and automation usage. The interface is specifically designed around the REST pattern semantics.
HTTP methods are used by the Redfish protocol for common CRUD operations and to retrieve header information.
Actions are used for expanding operations beyond CRUD type operations, but should be limited in use.
Media types are used to negotiate the type of data that is being sent in the body of a message.
HTTP status codes are used to indicate the server's attempt at processing the request. Extended error handling is used to return more information than the HTTP error code provides.
The ability to send secure messages is important; the Security clause of this document describes specific TLS requirements.
Some operations may take longer than required for synchronous return semantics. Consequently, deterministic asynchronous semantic are included in the architecture.
HTTP is ideally suited to a RESTful interface. This clause describes how HTTP is used in the Redfish interface and what constraints are added on top of HTTP to assure interoperability of Redfish compliant implementations.
A URI is used to identify a resource, including the base service and all Redfish resources.
To begin operations, a client must know a URI for a resource.
The base resource URI is well known and is based on the protocol version. Discovering the URIs to additional resources is done through observing the associated resource links returned in previous responses. This type of API that is consumed by navigating URIs returned by the service is known as a Hypermedia API.
Redfish considers three parts of the URI as described in RFC3986.
The first part includes the scheme and authority portions of the URI. The second part includes the root service and version. The third part is a unique resource identifier.
For example, in the following URL:
Example: https://mgmt.vendor.com/redfish/v1/Systems/1
https://mgmt.vendor.com)./redfish/v1/).Systems/1).The scheme and authority part of the URI shall not be considered part of the unique identifier of the resource. This is due to redirection capabilities and local operations which may result in the variability of the connection portion. The remainder of the URI (the service and resource paths) is what uniquely identifies the resource, and this is what is returned in all Redfish payloads.
For example, a POST may return the following URI in the Location header of the response (indicating the new resource created by the POST):
Example: /redfish/v1/Systems/2
Assuming the client is connecting through an appliance named "mgmt.vendor.com", the full URI needed to access this new resource is https://mgmt.vendor.com/redfish/v1/Systems/2.
URIs, as described in RFC3986, may also contain a query (?query) and a frag (#frag) components. Queries are addressed in the clause Query Parameters. Fragments (frag) shall be ignored by the server when used as the URI for submitting an operation.
An attractive feature of the RESTful interface is the very limited number of operations which are supported. The following table describes the general mapping of operations to HTTP methods. If the value in the column entitled "required" has the value "yes" then the HTTP method shall be supported by a Redfish interface.
| 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, CORs preflight | No |
Other HTTP methods are not allowed and shall receive a 405 response.
HTTP redirect allows a service to redirect a request to another URL. Among other things, this enables Redfish resources to alias areas of the data model.
NOTE: Refer to the Security clause for security implications of HTTP Redirect
Some resources may be available in more than one type of representation. The type of representation is indicated by the media type.
In HTTP messages the media type is specified in the Content-Type header. A client can tell a service that it wants the response to be sent using certain media types by setting the HTTP Accept header to a list of the acceptable media types.
Clients may request compression by specifying an Accept-Encoding header in the request.
In order to reduce the cases of unnecessary RESTful accesses to resources, the Redfish Service should support associating a separate ETag with each resource.
The ETag is generated and provided as part of the resource payload because the service is in the best position to know if the new version of the object is different enough to be considered substantial. There are two types of ETags: weak and strong.
This specification does not mandate a particular algorithm for creating the ETag, but ETags should be highly collision-free. An ETag could be a hash, a generation ID, a time stamp or some other value that changes when the underlying object changes.
If a client PUTs or PATCHes a resource, it should include an ETag in the HTTP If-Match/If-None-Match header from a previous GET.
In addition to returning the ETag property on each resource,
The format of the ETag header is:
ETag: W/"<string>"
The protocol version is separate from the version of the resources or the version of the Redfish Schema supported by them.
Each version of the Redfish protocol is strongly typed. This is accomplished using the URI of the Redfish Service in combination with the resource obtained at that URI, called the ServiceRoot.
The root URI for this version of the Redfish protocol shall be "/redfish/v1/".
While the major version of the protocol is represented in the URI, the major version, minor version and errata version of the protocol are represented in the Version property of the ServiceRoot resource, as defined in the Redfish Schema for that resource. The protocol version is a string of the form:
MajorVersion.MinorVersion.Errata
where
Any resource discovered through links found by accessing the root service or any service or resource referenced using references from the root service shall conform to the same version of the protocol supported by the root service.
A GET on the resource "/redfish" shall return the following body:
{
"v1": "/redfish/v1/"
}
Redfish is a hypermedia API with a small set of defined URIs. All other resources are accessible via opaque URIs referenced from the root service. The following Redfish-defined URIs shall be supported by a Redfish Service:
| URI | Description |
|---|---|
| /redfish | The URI that is used to return the version |
| /redfish/v1/ | The URI for the Redfish Service Root |
| /redfish/v1/odata | The URI for the Redfish OData Service Document |
| /redfish/v1/$metadata | The URI for the Redfish Metadata Document |
In addition, the following URI without a trailing slash shall be either Redirected to the Associated Redfish-defined URI shown in the table below or treated by the service as the equivalent URI to the associated Redfish-defined URI:
| URI | Associated Redfish-Defined URI |
|---|---|
| /redfish/v1 | /redfish/v1/ |
All relative URIs used by the service shall start with a double forward slash ("//") and include the authority (e.g., //mgmt.vendor.com/redfish/v1/Systems) or a single forward slash ("/") and include the absolute-path (e.g., /redfish/v1/Systems).
This clause describes the requests that can be sent to Redfish Services.
HTTP defines headers that can be used in request messages. The following table defines those headers and their requirements for Redfish Services. Note that these are requirements for the Redfish Services, and not the clients sending the HTTP requests.
| Header | Required | Supported Values | Description |
|---|---|---|---|
| Accept | Yes | RFC 7231 | Indicates to the server what media type(s) this client is prepared to accept. Services shall support requests for resources with an Accept header including application/json or application/json;charset=utf-8. Services shall support requests for metadata with an Accept header including application/xml or application/xml;charset=utf-8. |
| Accept-Encoding | No | RFC 7231 | Indicates if gzip encoding can be handled by the client. If an Accept-Encoding header is present in a request and the service cannot send a response which is acceptable according to the Accept-Encoding header, then the service should respond with status code 406. Services should not return responses gzip encoded if the Accept-Encoding header is not present in the request. |
| Accept-Language | No | RFC 7231 | This header is used to indicate the language(s) requested in the response. If this header is not specified, the appliance default locale will be used. |
| Content-Type | Conditional | RFC 7231 | Describes the type of representation used in the message body. Content-Type shall be required in requests that include a request body. Services shall accept Content-Type values of application/json or application/json;charset=utf-8. |
| Content-Length | No | RFC 7231 | Describes the size of the message body. An optional means of indicating size of the body uses Transfer-Encoding: chunked, which does not use the Content-Length header. If a service does not support Transfer-Encoding and needs Content-Length instead, the service will respond with status code 411. |
| OData-MaxVersion | No | 4.0 | Indicates the maximum version of OData that an odata-aware client understands |
| OData-Version | Yes | 4.0 | Services shall reject requests which specify an unsupported OData version. If a service encounters a version that it does not support, the service should reject the request with status code [412] (#status-412). If client does not specify an Odata-Version header, the client is outside the boundaries of this specification. |
| Authorization | Conditional | RFC 7235, Section 4.2 | Required for Basic Authentication |
| User-Agent | Yes | RFC 7231 | Required for tracing product tokens and their version. Multiple product tokens may be listed. |
| Host | Yes | RFC 7230 | Required to allow support of multiple origin hosts at a single IP address. |
| Origin | Yes | W3C CORS, Section 5.7 | Used to allow web applications to consume Redfish Service while preventing CSRF attacks. |
| Via | No | RFC 7230 | Indicates network hierarchy and recognizes message loops. Each pass inserts its own VIA. |
| Max-Forwards | No | RFC 7231 | Limits gateway and proxy hops. Prevents messages from remaining in the network indefinitely. |
| If-Match | Conditional | RFC 7232 | If-Match shall be supported on PUT and PATCH requests for resources for which the service returns ETags, to ensure clients are updating the resource from a known state. |
| If-None-Match | No | RFC 7232 | If this HTTP header is present, the service will only return the requested resource if the current ETag of that resource does not match the ETag sent in this header. If the ETag specified in this header matches the resource's current ETag, the status code returned from the GET will be 304. |
| Header | Required | Supported Values | Description |
|---|---|---|---|
| X-Auth-Token | Yes | Opaque encoded octet strings | Used for authentication of user sessions. The token value shall be indistinguishable from random. |
The GET method is used to retrieve a representation of a resource. The service will return the representation using one of the media types specified in the Accept header, subject to requirements in the Media Types clause Media Types. If the Accept header is not present, the service will return the resources representations as application/json.
The root URL for Redfish version 1 services shall be "/redfish/v1/".
The root URL for the Service returns a ServiceRoot resource as defined by this specification.
Services shall not require authentication in order to retrieve the service root and "/redfish" documents.
Redfish Services shall expose a metadata document describing the service at the "/redfish/v1/$metadata" resource. This metadata document describes the resources available at the root, and references additional metadata documents describing the full set of resource types exposed by the service.
Services shall not require authentication in order to retrieve the metadata document.
Redfish Services shall expose an OData Service Document, at the "/redfish/v1/odata" resource. This service document provides a standard format for enumerating the resources exposed by the service, enabling generic hypermedia-driven OData clients to navigate to the resources of the service.
Services shall not require authentication in order to retrieve the service document.
Clients request resources by issuing GET requests to the URI for the individual resource. The URI for a resource may be obtained from a resource identifier property returned in a previous request (for example, within the links clause of a previously returned resource). Services may, but are not required to, support the convention of retrieving individual properties of a Resource by appending a segment containing the property name to the URI of the resource.
When the resource addressed is a Resource Collection, the client may use the following paging query options to specify that a subset of the Members of that Resource Collection be returned. These paging query options apply specifically to the "Members" array property within a Resource Collection.
| Attribute | Description | Example |
|---|---|---|
| $skip | Integer indicating the number of Members in the Resource Collection to skip before retrieving the first resource. | http://resourcecollection?$skip=5 |
| $top | Integer indicating the number of Members to include in the response. The minimum value for this parameter is 1. The default behavior is to return all Members. | http://resourcecollection?$top=30 |
Retrieving a Resource Collection is done by sending the HTTP GET method to the URI for that resource. The response includes properties of the Resource Collection including an array of its Members. A subset of the Members can be returned using client paging query parameters.
No requirements are placed on implementations to return a consistent set of Members when a series of requests using paging query parameters are made over time to obtain the entire set of members. It is possible that this could result in missed or duplicate elements being retrieved if multiple GETs are used to retrieve the Members array instances using paging.
The HEAD method differs from the GET method in that it MUST NOT return message body information. However, all of the same meta information and status codes in the HTTP headers will be returned as though a GET method were processed, including authorization checks.
Clients create, modify, and delete resources by issuing the appropriate Create, Update, Replace or Delete operation, or by invoking an Action on the resource. Services return a status code 405 if the specified resource exists but does not support the requested operation. If a client (4xx) or service (5xx) status code is returned, the resource shall not be modified as a result of the operation.
The PATCH method is the preferred method used to perform updates on pre-existing resources. Changes to the resource are sent in the request body. Properties not specified in the request body are not directly changed by the PATCH request. The response is either empty or a representation of the resource after the update was done. The implementation may reject the update operation on certain fields based on its own policies and, if so, shall not apply any of the update requested.
Services may have null entries for properties that are JSON arrays to show the number of entries a client is allowed to use in a PATCH request. Within a PATCH request, unchanged members within a JSON array may be specified as empty JSON objects, and clearing members within a JSON array may be specified with null.
OData markup (resource identifiers, type, etag and links) are ignored on Update.
The PUT method is used to completely replace a resource. Properties omitted from the request body are reset to their default value.
The POST method is used to create a new resource. The POST request is submitted to the Resource Collection in which the new resource is to belong.
Submitting a POST request to a Resource Collection is equivalent to submitting the same request to the Members property of that Resource Collection. Services that support adding Members to a Resource Collection shall support both forms.
The body of the create request contains a representation of the object to be created. The service may ignore any service controlled attributes (e.g., id), forcing those attributes to be overridden by the service. The service shall set the Location header to the URI of the newly created resource. The response to a successful create request should be 201 (Created) and may include a response body containing a representation of the newly created resource conforming to the schema of the created resource.
The DELETE method is used to remove a resource.
Services may return status code 404 or a success code if the resource has already been deleted.
The POST method is used to initiate operations on the object (such as Actions).
Custom actions are requested on a resource by sending the HTTP POST method to the URI of the action. If the actions property within a resource does not specify a target property, then the URI of an action shall be of the form:
ResourceUri/Actions/QualifiedActionName
where
The first parameter of a bound function is the resource on which the action is being invoked. The remaining parameters are represented as name/value pairs in the body of the request.
Clients can query a resource directly to determine the actions that are available as well as valid parameter values for those actions. Some parameter information may require the client to examine the Redfish Schema corresponding to the resource.
For instance, if a Redfish Schema document http://redfish.dmtf.org/schemas/v1/ComputerSystem_v1.xml defines a Reset action in the ComputerSystem namespace, bound to the ComputerSystem.v1_0_0.Actions type, such as this example:
<Schema Name="ComputerSystem">
...
<Action Name="Reset" IsBound="true">
<Parameter Name="Resource" Type="ComputerSystem.v1_0_0.Actions"/>
<Parameter Name="ResetType" Type="Resource.ResetType"/>
</Action>
...
</Schema>
And a computer system resource contains an Actions property such as this:
...
"Actions": {
"#ComputerSystem.Reset": {
"target":"/redfish/v1/Systems/1/Actions/ComputerSystem.Reset",
"ResetType@Redfish.AllowableValues": [
"On",
"ForceOff",
"GracefulRestart",
"GracefulShutdown",
"ForceRestart",
"Nmi",
"ForceOn",
"PushPowerButton"
]
}
}
...Then the following would represent a possible request for the Action:
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"
}
Redfish defines four types of responses:
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 | Describes the OData version of the payload that the response conforms to. |
| Content-Type | Yes | RFC 7231 | Describes 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 | Describes the encoding that has been performed on the media type |
| Content-Length | No | RFC 7231 | Describes the size of the message body. An optional means of indicating size of the body uses Transfer-Encoding: chunked, which does not use the Content-Length header. If a service does not support Transfer-Encoding and needs Content-Length instead, the service will respond with status code 411. |
| ETag | Conditional | RFC 7232 | An identifier for a specific version of a resource, often a message digest. Etags shall be included on responses to GETs of ManagerAccount objects. |
| Server | Yes | RFC 7231 | Required to describe 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 | Indicates 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 which create user sessions. |
| Cache-Control | Yes | RFC 7234 | This header shall be supported and is meant to indicate whether a response can be cached or not. |
| Via | No | RFC 7230 | Indicates network hierarchy and recognizes message loops. Each pass inserts its own VIA. |
| 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 specified Request URI. Should 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 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. In addition to
links from the resource, the URL of the JSON Schema for the resource shall be
returned with a rel=describedby. URLs of the JSON Schema for an annotation should be returned without a rel=describedby. If the referenced JSON Schema is a versioned schema, it shall match the version contained in the value of the @odata.id property returned in this 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
Link header(s) shall be returned on HEAD and a Link header satisfying
rel=describedby shall be returned on GET and HEAD and a Link header satisfying Annotations should be returned on GET and HEAD.
HTTP defines status codes that can be returned in response messages.
Where the HTTP status code indicates a failure, the response body contains an extended error resource to provide the client more meaningful and deterministic error semantics.
NOTE: Refer to the Security clause for security implications of extended errors
The following table lists some of the common HTTP status codes. Other codes may be returned by the service as appropriate. See the Description column for a description of the status code 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 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 resource 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 server recognized the credentials in the request, but those credentials do not possess authorization to perform this request. |
| 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 which provides a list of methods that are supported by the resource identified by the Request-URI. |
| 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 attributes that work in a linked manner using incompatible values). |
| 410 Gone | The requested resource is no longer available at the server and no forwarding address is known. This condition is expected to be considered permanent. Clients with link editing capabilities SHOULD delete references to the Request-URI after user approval. If the server 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 | 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. |
| 500 Internal Server Error | The server 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 server does not (currently) support the functionality required to fulfill the request. This is the appropriate response when the server does not recognize the request method and is not capable of supporting the method for any resource. |
| 503 Service Unavailable | The server is currently unable to handle the request due to temporary overloading or maintenance of the server. |
Metadata describes resources, Resource Collections, capabilities and service-dependent behavior to generic consumers, including OData client tools and applications 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, to request and interpret a JSON representation of a resource defined in this specification.
The service metadata describes top-level resources and resource types of the service according to OData-Schema. The Redfish Service Metadata is represented as an XML document with a root element named "Edmx", defined in the http://docs.oasis-open.org/odata/ns/edmx" namespace, and with an OData Version attribute equal to "4.0".
<edmx:Edmx xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx" Version="4.0">
<!-- edmx:Reference and edmx:Schema elements go here -->
</edmx:Edmx>
The service metadata shall include the namespaces for each of the Redfish resource types, along with the "RedfishExtensions.v1_0_0" namespace. These references may use the standard URI for the hosted Redfish Schema definitions (i.e., on http://redfish.dmtf.org/schemas) or a URI to a local version of the Redfish Schema that shall be identical to the hosted version.
<edmx:Reference Uri="http://redfish.dmtf.org/schemas/v1/AccountService_v1.xml">
<edmx:Include Namespace="AccountService"/>
<edmx:Include Namespace="AccountService.v1_0_0"/>
</edmx:Reference>
<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 metadata shall include an entity container that defines the top level resources and Resource Collections. An implementation may extend the ServiceContainer defined in the ServiceRoot.v1_0_0 schema and may include additional resources.
<edmx:DataServices>
<Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="Service">
<EntityContainer Name="Service" Extends="ServiceRoot.v1_0_0.ServiceContainer"/>
</Schema>
</edmx:DataServices>
The metadata document may reference additional schema documents describing OEM-specific extensions used by the service, for example custom types for additional Resource Collections.
<edmx:Reference Uri="http://contoso.org/Schema/CustomTypes">
<edmx:Include Namespace="CustomTypes"/>
</edmx:Reference>
The service can annotate sets, types, actions and parameters with Redfish-defined or custom annotation terms. These annotations are typically in a separate Annotations file referenced from the service metadata document using the IncludeAnnotations directive.
<edmx:Reference Uri="http://service/metadata/Service.Annotations">
<edmx:IncludeAnnotations TermNamespace="Annotations.v1_0_0"/>
</edmx:Reference>
The annotation file itself specifies the Target Redfish Schema element being annotated, the Term being applied, and the value of the term:
<Annotations Target="ComputerSystem.Reset/ResetType">
<Annotation Term="Annotation.AdditionalValues">
<Collection>
<String>Update and Restart</String>
<String>Update and PowerOff</String>
</Collection>
</Annotation>
</Annotations>
The OData Service Document serves as a top-level entry point for generic OData clients.
{
"@odata.context": "/redfish/v1/$metadata",
"value": [
{
"name": "Service",
"kind": "Singleton",
"url": "/redfish/v1/"
},
{
"name": "Systems",
"kind": "Singleton",
"url": "/redfish/v1/Systems"
},
{
"name": "Chassis",
"kind": "Singleton",
"url": "/redfish/v1/Chassis"
},
{
"name": "Managers",
"kind": "Singleton",
"url": "/redfish/v1/Managers"
},
...
]
}
The OData Service Document shall be returned as a JSON object, using the MIME type application/json.
The JSON object shall contain a context property named "@odata.context" with a value of "/redfish/v1/$metadata". This context tells a generic OData client how to find the service metadata describing the types exposed by the service.
The JSON object shall include a property named "value" whose value is a JSON array containing an entry for the service root and each resource that is a direct child of the service root.
Each entry shall be represented as a JSON object and shall include a "name" property whose value is a user-friendly name of the resource, a "kind" property whose value is "Singleton" for individual resources (including Resource Collections) or "EntitySet" for top-level Resource Collections, and a "url" property whose value is the relative URL for the top-level resource.
Resources are returned as JSON payloads, using the MIME type application/json. Resource property names match the case specified in the Schema.
See also Resource Collection responses.
Responses that represent a single resource shall contain a context property named "@odata.context" describing the source of the payload. The value of the context property shall be the context URL that describes the resource according to OData-Protocol.
The context URL for a resource is of one of the following two forms:
MetadataUrl#ResourceType[(Selectlist)] MetadataUrl#ResourcePath[(Selectlist)]/$entity
where
If a response contains a subset of the properties defined in the Redfish Schema for a type, then the context URL shall specify the subset of properties included. An asterix (*) can be used to specify "all structural properties" for a given resource.
Expanded reference properties shall be included in the select list if the result includes a subset of the properties defined for the expanded resource.
For example, the following context URL specifies that the result contains a single ComputerSystem resource:
...
"@odata.context":"/redfish/v1/$metadata#ComputerSystem.ComputerSystem"
...Resources in a response shall include a unique identifier property named "@odata.id". The value of the identifier property shall be the unique identifier for the resource.
Resources identifiers shall be represented in JSON payloads as strings that conform to the rules for URI paths as defined in Section 3.3, Path of RFC3986. Resources within the same authority as the request URI shall be represented according to the rules of path-absolute defined by that specification. That is, they shall always start with a single forward slash ("/"). Resources within a different authority as the request URI shall start with a double-slash ("//") followed by the authority and path to the resource.
The resource identifier is the canonical URL for the resource and can be used to retrieve or edit the resource, as appropriate.
All resources in a response shall include a type property named "@odata.type". The value of the type property shall be a URL fragment that specifies the type of the resource as defined within, or referenced by, the metadata document and shall be of the form:
#Namespace.TypeName
where
ETags provide the ability to conditionally retrieve or update a resource. Resources should include an ETag property named "@odata.etag". The value of the ETag property is the Etag for a resource.
Primitive properties shall be returned as JSON values according to the following table.
| Type | JSON Representation |
|---|---|
| Edm.Boolean | Boolean |
| Edm.DateTimeOffset | String, formatted as specified in DateTime Values |
| Edm.Decimal | Number, optionally containing a decimal point |
| Edm.Double | Number, optionally containing a decimal point and optionally containing an exponent |
| Edm.Guid | String, matching the pattern ([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}) |
| Edm.Int64 | Number with no decimal point |
| Edm.String | String |
When receiving values from the client, services should support other valid representations of the data within the specified JSON type. In particular, services should support valid integer and decimal values written in exponential notation and integer values containing a decimal point with no non-zero trailing digits.
DateTime values shall be returned as JSON strings according to the ISO 8601 "extended" format, with time offset or UTC suffix included, of the form:
*YYYY*-*MM*-*DD* T *hh*:*mm*:*ss*[.*SSS*] (Z | (+ | - ) *hh*:*mm*)
where:
Structured properties, defined as complex types or expanded resource types, are returned as JSON objects. The type of the JSON object is specified in the Redfish Schema definition of the property containing the structured value.
Available actions for a resource are represented as individual properties nested under a single structured property on the resource named "Actions".
Actions are represented by a property nested under "Actions" whose name is the unique URI that identifies the action. This URI shall be of the form:
#Namespace.ActionName
where
The client may use this fragment to identify the action definition within the referenced Redfish Schema document associated with the specified namespace.
The value of the property is a JSON object containing a property named "target" whose value is a relative or absolute URL used to invoke the action.
The property representing the available action may be annotated with the AllowableValues annotation in order to specify the list of allowable values for a particular parameter.
For example, the following property represents the Reset action, defined in the ComputerSystem namespace:
...
"#ComputerSystem.Reset": {
"target":"/redfish/v1/Systems/1/Actions/ComputerSystem.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:
{
"ResetType": "On"
}
The property representing the action may be annotated with the "AllowableValues" annotation in order to specify the list of allowable values for a particular parameter.
The set of allowable values is specified by including a property whose name is the name of the parameter followed by "@Redfish.AllowableValues", and whose value is a JSON array of strings representing the allowable values for the parameter.
References to other resources are represented by the links property on the resource.
The links property shall be named "Links" and shall contain a property for each non-contained reference property defined in the Redfish Schema for that type. For single-valued reference properties, the value of the property shall be the single related resource id. For collection-valued reference properties, the value of the property shall be the array of related resource ids.
The links property shall also include an OEM property for navigating vendor-specific links.
A reference to a single resource is returned as a JSON object containing a single resource-identifier-property whose name is the name of the relationship and whose value 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 returned as an array of JSON objects whose name is the name of the relationship. Each member of the array is a JSON object containing a single resource-identifier-property whose value is the uri of the referenced resource.
{
"Links" : {
"Contains" : [
{
"@odata.id":"/redfish/v1/Chassis/1"
},
{
"@odata.id":"/redfish/v1/Chassis/Encl1"
}
]
}
}
OEM-specific properties are nested under an OEM property.
Responses representing a single resource shall not be broken into multiple results.
Response objects may include extended information, for example information about properties that are not able to be updated. This information is represented as an annotation applied to a specific property of the JSON response or an entire JSON object.
A JSON object can be annotated with "@Message.ExtendedInfo" in order to specify object-level status information.
{
"@odata.context": "/redfish/v1/$metadata#SerialInterface.SerialInterface",
"@odata.id": "/redfish/v1/Managers/1/SerialInterfaces/1",
"@odata.type": "#SerialInterface.v1_0_0.SerialInterface",
"Name": "Managed Serial Interface 1",
"Description": "Management for Serial Interface",
"Status": {
"State": "Enabled",
"Health": "OK"
},
"InterfaceEnabled": true,
"SignalType": "Rs232",
"BitRate": "115200",
"Parity": "None",
"DataBits": "8",
"StopBits": "1",
"FlowControl": "None",
"ConnectorType": "RJ45",
"PinOut": "Cyclades",
"@Message.ExtendedInfo" : [
{
"MessageId": "Base.1.0.PropertyDuplicate",
"Message": "The property InterfaceEnabled was duplicated in the request.",
"RelatedProperties": [
"#/InterfaceEnabled"
],
"Severity": "Warning",
"Resolution": "Remove the duplicate property from the request body and resubmit the request if the operation failed."
}
]
}
The value of the property is an array of message objects.
An individual property within a JSON object can be annotated with extended information using "@Message.ExtendedInfo", prepended with the name of the property.
{
"@odata.context": "/redfish/v1/$metadata#SerialInterface.SerialInterface",
"@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."
}
]
}
The value of the property is an array of message objects.
A resource representation in JSON may include additional annotations represented as properties whose name is of the form:
[PropertyName]@Namespace.TermName
where
The client can get the definition of the annotation from the service metadata, or may ignore the annotation entirely, but should not fail reading the resource due to unrecognized annotations, including new annotations defined within the Redfish namespace.
Resource Collections are returned as a JSON object. The JSON object shall include a context, resource count, and array of Members, and may include a next link for partial results.
Responses shall contain a context property named "@odata.context" describing the source of the payload. The value of the context property shall be the context URL that describes the Resource Collection according to OData-Protocol.
The context URL for a Resource Collection is of one of the following two forms:
MetadataUrl.#CollectionResourceType MetadataUrl.#CollectionResourcePath
where
The total number of resources (members) available in the Resource Collection is represented through the count property. The count property shall be named "Members@odata.count" and its value shall be the total number of members available in the Resource Collection. This count is not affected by the $top or $skip query parameters.
The Members of the Resource Collection of resources are returned as a JSON array, where each element of the array is a JSON object whose type is specified in the Redfish Schema document describing the containing type. The name of the property representing the members of the collection shall be "Members". The Members property shall not be null. Empty collections shall be returned in JSON as an empty array.
Responses may contain a subset of the members of the full Resource Collection. For partial Resource Collections the response includes a next link property named "Members@odata.nextLink". The value of the next link property shall be an opaque URL to a resource, with the same @odata.type, containing the next set of partial members. 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.
The value of the count property represents the total number of resources available if the client enumerates all pages of the Resource Collection.
A JSON object representing a Resource Collection may include additional annotations represented as properties whose name is of the form:
@Namespace.TermName
where
The client can get the definition of the annotation from the service metadata, or may ignore the annotation entirely, but should not fail reading the response due to unrecognized annotations, including new annotations defined within the Redfish namespace.
HTTP response status codes alone often do not provide enough information to enable deterministic error semantics. For example, if a client does a PATCH and some of the properties do not match while others are not supported, simply returning an HTTP status code of 400 does not tell the client which values were in error. Error responses provide the client more meaningful and deterministic error semantics.
A Redfish Service may provide multiple error responses in the HTTP response in order to provide the client with as much information about the error situation as it can. Additionally, the service may provide Redfish standardized errors, OEM defined errors or both depending on the implementation's ablity to convey the most useful information about the underlying error.
Error responses are defined by an extended error resource, represented as a single JSON object with a property named "error" with the following properties.
| Property | Description |
|---|---|
| code | A string indicating a specific MessageId from the message registry. "Base.1.0.GeneralError" should be used only if there is no better message. |
| message | A human readable error message corresponding to the message in the message registry. |
| @Message.ExtendedInfo | An array of message objects describing one or more error message(s). |
{
"error": {
"code": "Base.1.0.GeneralError",
"message": "A general error has occurred. See ExtendedInfo for more information.",
"@Message.ExtendedInfo": [
{
"@odata.type" : "/redfish/v1/$metadata#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" : "/redfish/v1/$metadata#Message.v1_0_0.Message",
"MessageId": "Base.1.0.PropertyNotWriteable",
"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"
}
]
}
}
Message Objects provide additional information about an object, property, or error response.
Messages are represented as a JSON object with the following properties:
| Property | Description |
|---|---|
| MessageId | String indicating a specific error or message (not to be confused with the HTTP status code). This code can be used to access a detailed message from a message registry. |
| Message | A human readable error message indicating the semantics associated with the error. This shall be the complete message, and not rely on substitution variables. |
| RelatedProperties | An optional array of JSON Pointers defining the specific properties within a JSON payload described by the message. |
| MessageArgs | An optional array of strings representing the substitution parameter values for the message. This shall be included in the response if a MessageId is specified for a parameterized message. |
| Severity | An optional string representing the severity of the error. |
| Resolution | An optional string describing recommended action(s) 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 specifying the complete human-readable error message.
MessageIds identify specific messages defined in a message registry.
The value of the MessageId property shall be of the form
RegistryName.MajorVersion.MinorVersion.MessageKey
where
The client can use the MessageId to search the message registry for the corresponding message.
The message registry approach has advantages for internationalization (since the registry can be translated easily) and light weight implementation (since large strings need not be included with the implementation).
One of the key tenets of the Redfish interface is the separation of protocol and data model. This clause describes common data model, resource, and Redfish Schema requirements.
All Redfish schemas produced, approved and published by the SPMF are available from the DMTF website at http://redfish.dmtf.org/schemas for download. Each folder in the Repository contains both CSDL and JSON Schema formats. The schema 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. |
| redfish.dmtf.org/schemas/v1 | All v1.xx schema files. Every v1.xx minor or errata release of each schema file. |
| redfish.dmtf.org/schemas/archive | Sub-folders contain schema files specific to a particular version release. |
Programs may access the Schema Repository using the redfish.dmtf.org/schemas/v1 durable URL, as this folder will contain each released version of each schema. Programs incorporating schema usage should implement a local schema cache to reduce latency, program requirements for Internet access and undue traffic burden on the DMTF website.
Types are identified by a Type URI. The URI for a type is of the form:
#Namespace.TypeName
where
The namespace for types defined by this specification is of the form:
ResourceTypeName.vMajorVersion_MinorVersion_Errata
where
An example of a valid type namespace might be "ComputerSystem.v1_0_0".
Types used within a JSON payload shall be defined in, or referenced by, the service metadata.
Resource types defined by this specification shall be referenced in JSON documents using the full (versioned) namespace name.
NOTE: Refer to the Security clause for security implications of Data Model & Schema
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.
Resource Name, Property Names, and constants such as Enumerations shall be Pascal-cased
Exceptions are allowed for the following cases:
For attributes that have units, or other special meaning, the unit identifier should be appended to the name. The current list includes:
Localization and translation of data or meta data is outside of the scope of version 1.0 of the Redfish Specification. Property names are never localized.
Individual resources and their dependent types and actions are defined within a Redfish schema document.
All Redfish types and properties shall include description and long description annotations.
The Description annotation can be applied to any type, property, action or parameter in order to provide a human-readable description of the Redfish Schema element.
The Description annotation is defined in http://docs.oasis-open.org/odata/odata/v4.0/os/vocabularies/Org.OData.Core.V1.xml.
The LongDescription annotation term can be applied to any type, property, action or parameter in order to provide a formal, normative specification of the schema element. Where the LongDescriptions in the Redfish schema files contain "shall" references, the service shall be required to conform with the statement.
The LongDescription annotation term is defined in http://docs.oasis-open.org/odata/odata/v4.0/os/vocabularies/Org.OData.Core.V1.xml.
Individual resources are defined as entity types within an OData Schema representation of the Redfish Schema according to OData-Schema. The representation may include annotations to facilitate automatic generation of JSON Schema representation of the Redfish Schema capable of validating JSON payloads.
Schema referenced from the implementation, either from the OData Service Document or the JSON Schema File representations, 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.
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>
Redfish Schemas may reference types defined in other schema documents. In the OData Schema representation, this is done by including a Reference element. In the JSON Schema representation, this is done with a $ref property.
The reference element specifies the Uri of the OData schema representation document describing the referenced type and has one or more child Include elements 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, and resource type definitions reference the Redfish Resource.v1_0_0 namespace for base types. Redfish OData Schema representations that include measures such as temperature, speed, or dimensions generally include the OData Measures namespace.
<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: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>
Resource types are defined within a namespace in the OData Schema representations. The namespace is defined through a Schema element that contains attributes for declaring the Namespace and local Alias for the schema.
The OData 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 go here -->
</Schema>
</edmx:DataServices>
Resource types are defined within a namespace using EntityType elements. The Name attribute specifies the name of the resource and the BaseType specifies the base type, if any.
Redfish resources derive from a common resource base type named "Resource" in the Resource.v1_0_0 namespace.
The EntityType contains the property and reference property elements that define the resource, as well as annotations describing the resource.
<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 Reference Property definitions go here -->
</EntityType>
All resources shall include Description and LongDescription annotations.
Structural properties of the resource are defined using the Property element. The Name attribute specifies the name of the property, and the Type its type.
Property names in the Request and Response JSON Payload shall match the casing of the value of the Name attribute.
Properties that must have a non-nullable value include the nullable attribute with a value of "false".
<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>
All properties shall include Description and LongDescription annotations.
Properties that are read-only are annotated with the Permissions annotation with a value of ODataPermission/Read.
Properties that are required to be implemented by all services are annotated with the required annotation.
Properties that have units associated with them can be annotated with the units annotation
Type of a property is specified by the Type attribute. The value of the type attribute may be a primitive type, a structured type, an enumeration type or a collection of primitive, structured or enumeration types.
Primitive types are prefixed with the "Edm" namespace prefix.
Redfish Services may use any of the following primitive types:
| Type | Meaning |
|---|---|
| Edm.Boolean | True or False |
| Edm.DateTimeOffset | Date and time with a time-zone |
| Edm.Decimal | Numeric values with fixed precision and scale |
| Edm.Double | IEEE 754 binary64 floating-point number (15-17 decimal digits) |
| Edm.Guid | A globally unique identifier |
| Edm.Int64 | Signed 64-bit integer |
| Edm.String | Sequence of UTF-8 characters |
Structured types are defined within a namespace using ComplexType elements. The Name attribute of the complex type specifies the name of the structured type. Complex types can include a BaseType attribute to specifies the base type, if any.
Structured types may be reused across different properties of different resource types.
<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 Reference Property definitions go here -->
</ComplexType>
Structured types can contain properties, reference properties and annotations.
Structured types shall include Description and LongDescription annotations.
Enumeration types are defined within a namespace using EnumType elements. The Name attribute of the enumeration type specifies the name of the enumeration type.
Enumeration types may be reused across different properties of different resource types.
EnumType elements 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>
Enumeration Types shall include Description and LongDescription annotations.
Enumeration Members shall include Description annotations.
The type attribute may specify a collection of primitive, structured or enumeration types.
The value of the type attribute for a collection-valued property is of the form:
Collection(NamespaceQualifiedTypeName)
where NamespaceQualifiedTypeName is the namespace qualified name of the primitive, structured, or enumeration type.
The AdditionalProperties annotation term is used to specify whether a type can contain additional properties outside of those defined. Types annotated with the AdditionalProperties annotation with a value of "False", shall not contain additional properties.
<Annotation Term="OData.AdditionalProperties"/>
The AdditionalProperties annotation term is defined in https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/spec/vocabularies/Org.OData.Core.V1.xml.
Properties may include the Nullable attribute with a value of false to specify that the property cannot contain null values. A property with a nullable attribute with a value of "true", or no nullable attribute, can accept null values.
<Property Name="Property1" Type="Edm.String" Nullable="false">
The Permissions annotation term can be applied to a property with the value of OData.Permission/Read in order to specify that it is read-only.
<Annotation Term="OData.Permissions" EnumMember="OData.Permission/Read"/>
The Permissions annotation term is defined in http://docs.oasis-open.org/odata/odata/v4.0/os/vocabularies/Org.OData.Core.V1.xml.
The Required annotation or Nullable attribute is used to specify that a property is required to be supported by services. Required properties shall be annotated with the Required annotation, or annotated with a Nullable attribute with a value of "false". All other properties are optional.
If an implementation supports a property, it shall always provide a value for that property. If a value is unknown, then null is an acceptable values in most cases. Properties not returned from a GET operation shall indicate that the property is not currently supported by the implementation.
<Annotation Term="Redfish.Required"/>
The Required annotation term is defined in http://redfish.dmtf.org/schemas/v1/RedfishExtensions_v1.xml.
The RequiredOnCreate annotation term is used to specify that a property is required to be specified on creation of the resource. Properties not annotated with the RequiredOnCreate annotation, or annotated with a Boolean attribute with a value of "false", are not required on create.
<Annotation Term="Redfish.RequiredOnCreate"/>
The RequiredOnCreate annotation term is defined in http://redfish.dmtf.org/schemas/v1/RedfishExtensions_v1.xml.
In addition to following naming conventions, properties representing units of measure shall be annotated with the Units annotation term in order to specify the units of measurement for the property.
The value of the annotation should be a string which 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 (e.g., Mebibyte (1024^2 bytes), which has the UCUM prefix "Mi" and symbol "By"), the case-sensitive "(c/s)" symbol for the prefix as listed in UCUM should be prepended to the unit symbol. For values which 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").
<Annotation Term="Measures.Unit" String="MiBy"/>
The Unit annotation term is defined in http://docs.oasis-open.org/odata/odata/v4.0/os/vocabularies/Org.OData.Measures.V1.xml.
Properties that reference other resources are represented as reference properties using the NavigationProperty element. The NavigationProperty element specifies the Name and namespace qualified Type of the related resource(s).
If the property references a single type, the value of the type attribute is the namespace qualified name of the related resource type.
<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>
If the property references a collection of resources, the value of the type attribute is of the form:
Collection(NamespaceQualifiedTypeName)
where NamespaceQualifiedTypeName is the namespace qualified name of the type of related resources.
<NavigationProperty Name="RelatedTypes" Type="Collection(MyTypes.TypeB)" Nullable="false">
<Annotation Term="OData.Description" String="This property represents a collection of related resources."/>
<Annotation Term="OData.LongDescription" String="This is the specification of the related property."/>
<Annotation Term="OData.AutoExpandReferences"/>
</NavigationProperty>
All reference properties shall include Description and LongDescription annotations.
Reference properties whose members are contained by the referencing resource are specified with the ContainsTarget attribute with a value of true.
For example, to specify that a Chassis resource contains a Power resource, you would specify ContainsTarget=true on the resource property representing the Power Resource within the Chassis type definition.
<NavigationProperty Name="Power" Type="Power.Power" ContainsTarget="true">
<Annotation Term="OData.Description" String="A reference to the power properties (power supplies, power policies, sensors) for this chassis."/>
<Annotation Term="OData.LongDescription" String="The value of this property shall be a reference to the resource that represents the power characteristics of this chassis and shall be of type Power."/>
<Annotation Term="OData.AutoExpandReferences"/>
</NavigationProperty>
Reference properties in a Redfish JSON payload are expanded to include the related resource id or collection of related resource ids. This behavior is expressed using the AutoExpandReferences annotation.
<Annotation Term="OData.AutoExpandReferences"/>
The AutoExpandReferences annotation term is defined in https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/spec/vocabularies/Org.OData.Core.V1.xml.
This term can be applied to a reference property in order to specify that the default behavior for the service is to expand the related resource or Resource Collection in responses.
<Annotation Term="OData.AutoExpand"/>
The AutoExpand annotation term is defined in https://tools.oasis-open.org/version-control/browse/wsvn/odata/trunk/spec/vocabularies/Org.OData.Core.V1.xml.
Actions are grouped under a property named "Actions".
<Property Name="Actions" Type="MyType.Actions">
The type of the Actions property is a structured type with a single OEM property whose type is a structured type with no defined properties.
<ComplexType Name="Actions">
<Property Name="OEM" Type="MyType.OEMActions"/>
</ComplexType>
<ComplexType Name="OEMActions"/>
Individual actions are defined within a namespace using Action elements. The Name attribute of the action specifies the name of the action. The IsBound attribute specifies that the action is bound to (appears as a member of) a resource or structured type.
The Action element contains one or more Parameter elements that specify the Name and Type of each parameter.
The first parameter is called the "binding parameter" and specifies the resource or structured type that the action appears as a member of (the type of the Actions property on the resource). The remaining Parameter elements describe additional parameters to be passed to the action.
<Action Name="MyAction" IsBound="true">
<Parameter Name="Thing" Type="MyType.Actions"/>
<Parameter Name="Parameter1" Type="Edm.Boolean"/>
</Action>
Companies, OEMs, and other organizations can define additional properties, links, and actions for common Redfish resources using the Oem property on resources, links, 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.
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. The base schema for Redfish-specified resources include an empty complex type property called "Oem" whose value can be used to encapsulate one or more OEM-specified complex properties. The Oem property in the standard Redfish schema is thus a predefined placeholder that is available for OEM-specific property definitions.
Correct use of the Oem property requires defining the metadata for an OEM-specified complex type that can be referenced within the Oem property. The following fragment is an example of an XML schema that defines a pair of OEM-specific properties under the complex type "AnvilType1". (Other schema elements that would typically be present, such as XML and OData schema description identifiers, are not shown in order to simplify the example).
<Schema Name="Contoso.v1_2_0">
...
<ComplexType Name="AnvilType1">
<Property Name="slogan" Type="Edm.String"/>
<Property Name="disclaimer" Type="Edm.String"/>
</ComplexType>
...
</Schema>
The next fragment shows an example of how the previous schema and the "AnvilType1" property type might appear in the instantiation of an Oem property as the result of a GET on a resource. The example shows two required elements in the use of the Oem property: A name for the object and a type property for the object. Detailed requirements for these elements are provided in the following clauses.
...
"Oem": {
"Contoso": {
"@odata.type": "http://Contoso.com/schemas/extensions.v1_2_0#contoso.AnvilType1",
"slogan": "Contoso anvils never fail",
"disclaimer": "* Most of the time"
}
}
...OEM-specified objects that are contained within the Oem property shall be valid JSON objects that follow the format of a Redfish complex type. The name of the object (property) shall uniquely identify the OEM or organization that manages the top of the namespace under which the property is defined. This is described in more detail in the following clause. The OEM-specified property 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.
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 may use 'Contoso', but Contoso.org must 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 namespacing 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 sub-organization "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.
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": "http://contoso.com/schemas/extensions.v1_2_1#contoso.AnvilTypes1",
"slogan": "Contoso anvils never fail",
"disclaimer": "* Most of the time"
},
"Contoso_biz": {
"@odata.type": "http://contoso.biz/schemas/extension1_1#RelatedSpeed",
"speed" : "ludicrous"
},
"EID_412_ASB_123": {
"@odata.type": "http://AnotherStandardsBody/schemas.v1_0_1#powerInfoExt",
"readingInfo": {
"readingAccuracy": "5",
"readingInterval": "20"
}
},
"Contoso_customers_customerA": {
"@odata.type" : "http://slingShots.customerA.com/catExt.2015#slingPower",
"AvailableTargets" : [ "rabbit", "duck", "runner" ],
"launchPowerOptions" : [ "low", "medium", "eliminate" ],
"powerSetting" : "eliminate",
"targetSetting" : "rabbit"
}
}
...OEM-specific actions can be defined by defining actions bound to the OEM property of the resource's Actions property type.
<Action Name="Ping" IsBound="true">
<Parameter Name="ContosoType" Type="MyType.OEMActions"/>
</Action>
</Schema>
Such bound actions appear in the JSON payload as properties of the Oem type, nested under an Actions property.
...
"Actions": {
"OEM": {
"Contoso.vx_x_x#Contoso.Ping": {
"target":"/redfish/v1/Systems/1/Actions/OEM/Contoso.Ping"
}
}
}
...This specification defines a set of common annotations for extending the definition of resource types used by Redfish. In addition, services may define custom annotations.
Services may apply annotations to resources in order to provide service-specific information about the type, such as whether the service supports modifications of particular properties.
Services can apply annotations to existing resources where those resources don't already define a value for the annotation. Services cannot change the value of an annotation applied as part of the resource definition.
Because service annotations may be applied to existing resource definitions, they are generally specified in a service-specific metadata document referenced by the service metadata.
This clause 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.
Common properties are defined in the base "Resource" Redfish Schema. For OData Schema Representations, this is in Resource_v1.xml and for JSON Schema Representations, this is in Resource.v1_0_0.json.
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 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 Description property is used to convey a human readable description of the resource. The type of the Description property shall be string.
The Status property represents the status of a resource.
The value of the status property is a common status object type as defined by this specification. By having a common representation of status, clients can depend on consistent semantics. The Status object is capable of indicating the current intended state, the state the resource has been requested to change to, the current actual state and any problem affecting the current state of the resource.
The Links property represents the links associated with the resource, as defined by that resources 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 Members property of a Resource Collection identifies the members of the collection.
The RelatedItem property represents links to a resource (or part of a resource) as defined by that resources schema definition. This is not intended to be a strong linking methodology like other references. Instead it is used to show a relationship between elements or sub-elements in disparate parts of the service. For example, since Fans may be in one area of the implementation and processors in another, RelatedItem can be used to inform the client that one is related to the other (in this case, the Fan is cooling the processor).
The Actions property contains the actions supported by a resource.
The OEM property is used for OEM extensions as defined in Schema Extensibility.
Collectively known as the Redfish Schema, the set of resource descriptions contains normative requirements on implementations conforming to this specification.
Redfish Resources are one of several general kinds:
Current Configuration resources represent the service's knowledge of the current state and configuration of the resource. This may be directly updatable with a PATCH or it may be read-only by the client and the client must PATCH to a separate Setting resource.
Setting resources represent the future state and configuration of the resource. This property is always associated with a resource through the Redfish.Settings annotation. Where the resource represents the current state, the settings resource represents the future intended state. The state of the resource is changed either directly, such as with a POST of an action or PUT request or indirectly, such as when a user reboots a machine outside of the Redfish Service.
Service resources represent components of the Redfish Service itself as well as dependent resources. While the complete list is discoverable only by traversing the Redfish Service tree, the list includes services like the Eventing service, Task management and Session management.
Registry resources are those resources that assist the client in interpreting Redfish resources beyond the Redfish Schema definitions. Examples of registries include Message Registries, Event Registries and enumeration registries, such as those used for BIOS. 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.
There are some situations that arise with certain kinds of resources that need to exhibit common semantic behavior.
Resources may be either absent or their state unknown at the time a client requests information about that resource. For removed resources where the URI is expected to remain constant (such as when a fan is removed), the resource should represent the State property of the Status object as "Absent". In this circumstance, any required or supported properties for which there is no known value shall be represented as null.
There are cases when deviations from the published Redfish Schema are necessary. An example is BIOS where different servers may have minor variations in available configuration settings. A provider may build a single schema that is a superset of the individual implementations. In order to support these variations, Redfish supports omitting parameters defined in the class schema in the current configuration object. The following rules apply:
Providers may split the schema resources into separate files such as Schema + String Registry, each with a separate URI and different Content-Encoding.
This clause covers the REST-based mechanism for subscribing to and receiving event messages.
The Redfish Service requires a client or administrator to create subscriptions to receive events. A subscription is created when an administrator sends an HTTP POST message to the URI of the subscription resource. 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.
There are two types of events generated in a Redfish Service - life cycle and alert.
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 attributes 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.
NOTE: Refer to the Security clause for security implications of Eventing.
The client locates the Event Service by traversing the Redfish Service interface. When the service has been discovered, clients subscribe to messages by sending a HTTP POST to the URL of the Resource Collection for "Subscriptions" in the Event Service. The Event Service is found off of the Service Root as described in the Redfish Schema for that service.
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 once a subscription has been registered with the service and do not receive events retroactively. Historical events are not retained by the service.
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
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.
Services that support asynchronous operations will implement the Task service & 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 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.
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).
Once the operation has completed, the Task Monitor shall return a the appropriate status code ( 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 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 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.
The Resource Tree, which is defined as the set of URIs and array elements within the implementation, must be consistent on a single service across device reboot and A/C power cycle, and must 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 must 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.
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.
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.
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'
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 backwards-compatible with previous minor revisions, then that minor version shall be appended, 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. 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:
Redfish devices may implement the additional SSDP messages defined by UPnP to announce their availability to software. This capability, if implemented, must 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.
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.
Implementations should support AES-256 based ciphers from the TLS suites.
Redfish implementations should consider supporting ciphers similar to below which 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
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.
Authentication Methods
Service shall support both "Basic Authentication" and "Redfish Session Login Authentication" (as described below under Session Management). Services shall not require a client to create a session when Basic Auth is used.
Services may implement other authentication mechanisms.
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.
Every request that establishes a secure channel shall be accompanied by an authentication header.
Session management is left to the implementation of the Redfish Service. This includes orphaned session timeout and number of simultaneous open 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 Section under the Sessions property. Both URIs shall be the same.
...
"SessionService": {
"@odata.id": "/redfish/v1/SessionService"
},
"Links": {
"Sessions": {
"@odata.id": "/redfish/v1/SessionService/Sessions"
}
}
...A Redfish session is created, without requiring an authentication header, by an HTTP POST to the SessionService' 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 includes:
Location: /redfish/v1/SessionService/Sessions/1
X-Auth-Token: <session-auth-token>
{
"@odata.context": "/redfish/v1/$metadata#Session.Session",
"@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 link 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 link that was returned in the Location header of the POST to logout 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 link. 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.
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.
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 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 then the session is automatically terminated.
A Redfish session is terminated when the client Logs-out. This is accomplished by performing a DELETE to the Session resource identified by the link 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.
The Authorization subsystem uses Roles and Privileges to control which users have what access to resources.
Roles:
Privileges:
User Management:
| Version | Date | Description |
|---|---|---|
| 1.0.5 | 2016-12-23 | 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 | 2016-8-28 | 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 must match the Role Name. | ||
| 1.0.3 | 2016-6-17 | 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 | 2016-3-31 | 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 ( |
||
| 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 must 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 | 2015-9-17 | 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 | 2015-8-4 | Initial release |