.. Copyright 2010 OpenStack, LLC All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Glance Authentication With Keystone =================================== Glance may optionally be integrated with Keystone. Setting this up is relatively straightforward: the Keystone distribution includes the requisite middleware and examples of appropriately modified ``glance-api.conf`` and ``glance-registry.conf`` configuration files in the ``examples/paste`` directory. Once you have installed Keystone and edited your configuration files, newly created images will have their `owner` attribute set to the tenant of the authenticated users, and the `is_public` attribute will cause access to those images for which it is `false` to be restricted to only the owner. .. note:: The exception is those images for which `owner` is set to `null`, which may only be done by those users having the ``Admin`` role. These images may still be accessed by the public, but will not appear in the list of public images. This allows the Glance Registry owner to publish images for beta testing without allowing those images to show up in lists, potentially confusing users. Configuring the Glance Client to use Keystone --------------------------------------------- Once the Glance API and Registry servers have been configured to use Keystone, you will need to configure the Glance client (``bin/glance``) to use Keystone as well. Just as with Nova, the specifying of authentication credentials is done via environment variables. The only difference being that Glance environment variables start with `OS_AUTH_` while Nova's begin with `NOVA_`. If you already have Nova credentials present in your environment, you can use the included tool, ``tools/nova_to_os_env.sh``, to create Glance-style credentials. To use this tool, verify that Nova credentials are present by running:: $ env | grep NOVA_ NOVA_USERNAME= NOVA_API_KEY= NOVA_PROJECT_ID= NOVA_URL= NOVA_AUTH_STRATEGY=keystone .. note:: If `NOVA_AUTH_STRATEGY=keystone` is not present, add that to your ``novarc`` file and re-source it. If the command produces no output at all, then you will need to source your ``novarc``. Also, make sure that `NOVA_URL` points to Keystone and not the Nova API server. Keystone will return the address for Nova and Glance's API servers via its "service catalog". Once Nova credentials are present in the environment, you will need to source the conervsion script:: $ source ./tools/nova_to_os_env.sh The final step is to verify that the `OS_AUTH_` crednetials are present:: $ env | grep OS_AUTH OS_AUTH_USER= OS_AUTH_KEY= OS_AUTH_TENANT= OS_AUTH_URL= OS_AUTH_STRATEGY=keystone Alternatively, these credentials may be specified using the following switches to the ``bin/glance`` command: -I USER, --username=USER User name used to acquire an authentication token -K PASSWORD, --password=PASSWORD Password used to acquire an authentication token -T TENANT, --tenant=TENANT Tenant name -N AUTH_URL, --auth_url=AUTH_URL Authentication URL -S STRATEGY, --auth_strategy=STRATEGY Authentication strategy (keystone or noauth) Or, if a pre-authenticated token is preferred, the following option allows the client-side interaction with keystone to be by-passed (useful if a long sequence of commands is being scripted): -A TOKEN, --auth_token=TOKEN Authentication token to use to identify the client to the glance server In general the command line switch takes precedence over the corresponding OS_AUTH_* environment variable, if both are set. Configuring the Glance servers to use Keystone ---------------------------------------------- Keystone is integrated with Glance through the use of middleware. The default configuration files for both the Glance API and the Glance Registry use a single piece of middleware called ``context``, which generates a request context without any knowledge of Keystone. In order to configure Glance to use Keystone, this ``context`` middleware must be replaced with two other pieces of middleware: the ``authtoken`` middleware and the ``auth-context`` middleware, both of which may be found in the Keystone distribution. The ``authtoken`` middleware performs the Keystone token validation, which is the heart of Keystone authentication. On the other hand, the ``auth-context`` middleware performs the necessary tie-in between Keystone and Glance; it is the component which replaces the ``context`` middleware that Glance uses by default. One other important concept to keep in mind is the *request context*. In the default Glance configuration, the ``context`` middleware sets up a basic request context; configuring Glance to use ``auth_context`` causes a more advanced context to be configured. It is also important to note that the Glance API and the Glance Registry use two different context classes; this is because the registry needs advanced methods that are not available in the default context class. The implications of this will be obvious in the below example for configuring the Glance Registry. Configuring Glance API to use Keystone -------------------------------------- Configuring Glance API to use Keystone is relatively straight forward. The first step is to ensure that declarations for the two pieces of middleware exist in the ``glance-api-paste.ini``. Here is an example for ``authtoken``:: [filter:authtoken] paste.filter_factory = keystone.middleware.auth_token:filter_factory service_protocol = http service_host = 127.0.0.1 service_port = 5000 auth_host = 127.0.0.1 auth_port = 35357 auth_protocol = http auth_uri = http://127.0.0.1:5000/ admin_token = 999888777666 The actual values for these variables will need to be set depending on your situation. For more information, please refer to the Keystone documentation on the ``auth_token`` middleware, but in short: * Those variables beginning with ``service_`` are only needed if you are using a proxy; they define the actual location of Glance. That said, they must be present. * Except for ``auth_uri``, those variables beginning with ``auth_`` point to the Keystone Admin service. This information is used by the middleware to actually query Keystone about the validity of the authentication tokens. * The ``auth_uri`` variable must point to the Keystone Auth service, which is the service users use to obtain Keystone tokens. If the user does not have a valid Keystone token, they will be redirected to this URI to obtain one. * The ``admin_token`` variable specifies the administrative token that Glance uses in its query to the Keystone Admin service. The other piece of middleware needed for Glance API is the ``auth-context``:: [filter:auth_context] paste.filter_factory = keystone.middleware.glance_auth_token:filter_factory Finally, to actually enable using Keystone authentication, the application pipeline must be modified. By default, it looks like:: [pipeline:glance-api] pipeline = versionnegotiation context apiv1app (Your particular pipeline may vary depending on other options, such as the image cache.) This must be changed by replacing ``context`` with ``authtoken`` and ``auth-context``:: [pipeline:glance-api] pipeline = versionnegotiation authtoken auth-context apiv1app Configuring Glance Registry to use Keystone ------------------------------------------- Configuring Glance Registry to use Keystone is also relatively straight forward. The same pieces of middleware need to be added to ``glance-registry-paste.ini`` as are needed by Glance API; see above for an example of the ``authtoken`` configuration. There is a slight difference for the ``auth-context`` middleware, which should look like this:: [filter:auth-context] context_class = glance.registry.context.RequestContext paste.filter_factory = keystone.middleware.glance_auth_token:filter_factory The ``context_class`` variable is needed to specify the Registry-specific request context, which contains the extra access checks used by the Registry. Again, to enable using Keystone authentication, the appropriate application pipeline must be selected. By default, it looks like: [pipeline:glance-registry-keystone] pipeline = authtoken auth-context registryapp To enable the above application pipeline, in your main ``glance-registry.conf`` configuration file, select the appropriate deployment flavor like so:: [paste_deploy] flavor = keystone Sharing Images With Others -------------------------- It is possible to allow a private image to be shared with one or more alternate tenants. This is done through image *memberships*, which are available via the `members` resource of images. (For more details, see :doc:`glanceapi`.) Essentially, a membership is an association between an image and a tenant which has permission to access that image. These membership associations may also have a `can_share` attribute, which, if set to `true`, delegates the authority to share an image to the named tenant.