Networking API v2.0 general information

The Networking API v2.0 is a ReSTful HTTP service that uses all aspects of the HTTP protocol including methods, URIs, media types, response codes, and so on. Providers can use existing features of the protocol including caching, persistent connections, and content compression. For example, providers who employ a caching layer can respond with a 203 code instead of a 200 code when a request is served from the cache. Additionally, providers can offer support for conditional GET requests by using ETags, or they may send a redirect in response to a GET request. Create clients so that these differences are accounted for.

Authentication and authorization

The Networking API v2.0 uses the OpenStack Identity service <https://docs.openstack.org/developer/keystone>`__ as the default authentication service. When Keystone is enabled, users that submit requests to the OpenStack Networking service must provide an authentication token in X-Auth-Token request header. You obtain the token by authenticating to the Keystone endpoint.

When Keystone is enabled, the tenant_id attribute is not required in create requests because the tenant ID is derived from the authentication token.

The default authorization settings allow only administrative users to create resources on behalf of a different tenant.

OpenStack Networking uses information received from Keystone to authorize user requests. OpenStack Networking handles the following types of authorization policies:

  • Operation-based policies specify access criteria for specific operations, possibly with fine-grained control over specific attributes.
  • Resource-based policies access a specific resource. Permissions might or might not be granted depending on the permissions configured for the resource. Currently available for only the network resource.

The actual authorization policies enforced in OpenStack Networking might vary from deployment to deployment.

Request and response formats

The Networking API v2.0 supports both JSON and XML data serialization request and response formats.

Request format

Use the Content-Type request header to specify the request format. This header is required for operations that have a request body.

The syntax for the Content-Type header is:

Content-Type: application/FORMAT

Where ``FORMAT`` is either json or xml.

Response format

Use one of the following methods to specify the response format:

Accept header

The syntax for the Accept header is:

Accept: application/FORMAT

Where ``FORMAT`` is either json or xml. The default format is json.

Query extension

Add an .xml or .json extension to the request URI. For example, the .xml extension in the following list networks URI request specifies that the response body is to be returned in XML format:

GET ``publicURL``/networks.xml

If you do not specify a response format, JSON is the default.

If the Accept header and the query extension specify conflicting formats, the format specified in the query extension takes precedence. For example, if the query extension is .xml and the Accept header specifies application/json, the response is returned in XML format.

You can serialize a response in a different format from the request format.

Filtering and column selection

The Networking API v2.0 supports filtering based on all top level attributes of a resource. Filters are applicable to all list requests.

For example, the following request returns all networks named foobar:

GET /v2.0/networks?name=foobar

When you specify multiple filters, the Networking API v2.0 returns only objects that meet all filtering criteria. The operation applies an AND condition among the filters.

Note

OpenStack Networking does not offer an OR mechanism for filters.

Alternatively, you can issue a distinct request for each filter and build a response set from the received responses on the client-side.

By default, OpenStack Networking returns all attributes for any show or list call. The Networking API v2.0 has a mechanism to limit the set of attributes returned. For example, return id.

You can use the fields query parameter to control the attributes returned from the Networking API v2.0.

For example, the following request returns only id and name for each network:

GET /v2.0/networks.json?fields=id&fields=name

Synchronous versus asynchronous plug-in behavior

The Networking API v2.0 presents a logical model of network connectivity consisting of networks, ports, and subnets. It is up to the OpenStack Networking plug-in to communicate with the underlying infrastructure to ensure packet forwarding is consistent with the logical model. A plug-in might perform these operations asynchronously.

When an API client modifies the logical model by issuing an HTTP POST, PUT, or DELETE request, the API call might return before the plug-in modifies underlying virtual and physical switching devices. However, an API client is guaranteed that all subsequent API calls properly reflect the changed logical model.

For example, if a client issues an HTTP PUT request to set the attachment for a port, there is no guarantee that packets sent by the interface named in the attachment are forwarded immediately when the HTTP call returns. However, it is guaranteed that a subsequent HTTP GET request to view the attachment on that port returns the new attachment value.

You can use the status attribute with the network and port resources to determine whether the OpenStack Networking plug-in has successfully completed the configuration of the resource.

Bulk-create

The Networking API v2.0 enables you to create several objects of the same type in the same API request. Bulk create operations use exactly the same API syntax as single create operations except that you specify a list of objects rather than a single object in the request body.

Bulk operations are always performed atomically, meaning that either all or none of the objects in the request body are created. If a particular plug-in does not support atomic operations, the Networking API v2.0 emulates the atomic behavior so that users can expect the same behavior regardless of the particular plug-in running in the background.

OpenStack Networking might be deployed without support for bulk operations and when the client attempts a bulk create operation, a 400 Bad request error is returned.

Sorting

You can use the ``sort_key`` and ``sort_dir`` parameters to sort the results of list operations. Currently sorting does not work with extended attributes of resource. The ``sort_key`` and ``sort_dir`` can be repeated, and the number of ``sort_key`` and ``sort_dir`` provided must be same. The ``sort_dir`` parameter indicates in which direction to sort. Acceptable values are asc (ascending) and desc (descending).

Sorting is optional feature of OpenStack Networking API, and it might be disabled. If sorting is disabled, the sorting parameters are ignored.

If a particular plug-in does not support sorting operations and sorting is enabled, the Networking API v2.0 emulates the sorting behavior so that users can expect the same behavior regardless of the particular plug-in that runs in the background.

Unfortunately OpenStack Networking does provide a mechanism to tell users if specific plug-ins support or have enabled sorting.

Extensions

The Networking API v2.0 is extensible.

The purpose of Networking API v2.0 extensions is to:

  • Introduce new features in the API without requiring a version change.
  • Introduce vendor-specific niche functionality.
  • Act as a proving ground for experimental functionalities that might be included in a future version of the API.

To programmatically determine which extensions are available, issue a GET request on the v2.0/extensions URI.

To query extensions individually by unique alias, issue a GET request on the /v2.0/extensions/*``alias_name``* URI. Use this method to easily determine if an extension is available. If the extension is not available, a 404 Not Found response is returned.

You can extend existing core API resources with new actions or extra attributes. Also, you can add new resources as extensions. Extensions usually have tags that prevent conflicts with other extensions that define attributes or resources with the same names, and with core resources and attributes. Because an extension might not be supported by all plug-ins, the availability of an extension varies with deployments and the specific plug-in in use.

Faults

The Networking API v2.0 returns an error response if a failure occurs while processing a request. OpenStack Networking uses only standard HTTP error codes. 4``nn`` errors indicate problems in the particular request being sent from the client.

Error

Description

400

Bad request

Malformed request URI or body

requested admin state invalid

Invalid values entered

Bulk operations disallowed

Validation failed

Method not allowed for request body (such as trying to update attributes that can be specified at create-time only)

404

Not Found

Non existent URI

Resource not found

409

Conflict

Port configured on network

IP allocated on subnet

Conflicting IP allocation pools for subnet

500

Internal server error

Internal OpenStack Networking error

503

Service unavailable

Failure in Mac address generation

Users submitting requests to the Networking API v2.0 might also receive the following errors:

  • 401 Unauthorized - If invalid credentials are provided.
  • 403 Forbidden - If the user cannot access a specific resource or perform the requested operation.