openstack-manuals/doc/user-guide/source/sdk_authenticate_against_compute_endpoint.rst

Authenticate against a Compute endpoint

To authenticate against a Compute endpoint, instantiate a novaclient.v_1_1.client.Client object:

from os import environ as env
import novaclient.v1_1.client as nvclient
nova = nvclient.Client(auth_url=env['OS_AUTH_URL'],
                       username=env['OS_USERNAME'],
                       api_key=env['OS_PASSWORD'],
                       project_id=env['OS_TENANT_NAME'],
                       region_name=env['OS_REGION_NAME'])

Alternatively, you can instantiate a novaclient.client.Client object and pass the version number:

from os import environ as env
import novaclient.client
nova = novaclient.client.Client("1.1", auth_url=env['OS_AUTH_URL'],
                                username=env['OS_USERNAME'],
                                api_key=env['OS_PASSWORD'],
                                project_id=env['OS_TENANT_NAME'],
                                region_name=env['OS_REGION_NAME'])

If you authenticate against an endpoint that uses a custom authentication back end, you must load the authentication plug-in and pass it to the constructor.

The Rackspace public cloud is an OpenStack deployment that uses a custom authentication back end. To authenticate against this cloud, you must install the rackspace-novaclient library that contains the Rackspace authentication plug-in, called rackspace. The following Python code shows the additional modifications required to instantiate a Client object that can authenticate against the Rackspace custom authentication back end.

import novaclient.auth_plugin
import novaclient.v1_1.client as nvclient
from os import environ as env
auth_system = 'rackspace'
auth_plugin = novaclient.auth_plugin.load_plugin('rackspace')
nova = nvclient.Client(auth_url=env['OS_AUTH_URL'],
                       username=env['OS_USERNAME'],
                       api_key=env['OS_PASSWORD'],
                       project_id=env['OS_TENANT_NAME'],
                       region_name=env['OS_REGION_NAME'],
                       auth_system='rackspace',
                       auth_plugin=auth_plugin)

If you set the OS_AUTH_SYSTEM environment variable, check for this variable in your Python script to determine whether you need to load a custom authentication back end:

import novaclient.auth_plugin
import novaclient.v1_1.client as nvclient
from os import environ as env
auth_system = env.get('OS_AUTH_SYSTEM', 'keystone')
if auth_system != "keystone":
  auth_plugin = novaclient.auth_plugin.load_plugin(auth_system)
else:
  auth_plugin = None
nova = nvclient.Client(auth_url=env['OS_AUTH_URL'],
                       username=env['OS_USERNAME'],
                       api_key=env['OS_PASSWORD'],
                       project_id=env['OS_TENANT_NAME'],
                       region_name=env['OS_REGION_NAME'],
                       auth_system=auth_system,
                       auth_plugin=auth_plugin)