=================
Identity concepts
=================

Authentication
    The process of confirming the identity of a user. To confirm an incoming
    request, OpenStack Identity validates a set of credentials users
    supply. Initially, these credentials are a user name and password, or a
    user name and API key. When OpenStack Identity validates user credentials,
    it issues an authentication token. Users provide the token in
    subsequent requests.

Credentials
    Data that confirms the identity of the user. For example, user
    name and password, user name and API key, or an authentication
    token that the Identity service provides.

Domain
    An Identity service API v3 entity. Domains are a collection of
    projects and users that define administrative boundaries for
    managing Identity entities. Domains can represent an
    individual, company, or operator-owned space. They expose
    administrative activities directly to system users. Users can be
    granted the administrator role for a domain. A domain
    administrator can create projects, users, and groups in a domain
    and assign roles to users and groups in a domain.

Endpoint
    A network-accessible address, usually a URL, through which you can
    access a service. If you are using an extension for templates, you
    can create an endpoint template that represents the templates of
    all consumable services that are available across the regions.

Group
    An Identity service API v3 entity. Groups are a collection of
    users owned by a domain. A group role, granted to a domain
    or project, applies to all users in the group. Adding or removing
    users to or from a group grants or revokes their role and
    authentication to the associated domain or project.

OpenStackClient
    A command-line interface for several OpenStack services including
    the Identity API. For example, a user can run the
    :command:`openstack service create` and
    :command:`openstack endpoint create` commands to register services
    in their OpenStack installation.

Project
    A container that groups or isolates resources or identity objects.
    Depending on the service operator, a project might map to a
    customer, account, organization, or tenant.

Region
    An Identity service API v3 entity. Represents a general division
    in an OpenStack deployment. You can associate zero or more
    sub-regions with a region to make a tree-like structured hierarchy.
    Although a region does not have a geographical connotation, a
    deployment can use a geographical name for a region, such as ``us-east``.

Role
    A personality with a defined set of user rights and privileges to
    perform a specific set of operations. The Identity service issues
    a token to a user that includes a list of roles. When a user calls
    a service, that service interprets the user role set, and
    determines to which operations or resources each role grants
    access.

Service
    An OpenStack service, such as Compute (nova), Object Storage
    (swift), or Image service (glance), that provides one or more
    endpoints through which users can access resources and perform
    operations.

Token
    An alpha-numeric text string that enables access to OpenStack APIs
    and resources. A token may be revoked at any time and is valid for
    a finite duration. While OpenStack Identity supports token-based
    authentication in this release, it intends to support additional
    protocols in the future. OpenStack Identity is an integration
    service that does not aspire to be a full-fledged identity store
    and management solution.

User
    A digital representation of a person, system, or service that uses
    OpenStack cloud services. The Identity service validates that
    incoming requests are made by the user who claims to be making the
    call. Users have a login and can access resources by using
    assigned tokens. Users can be directly assigned to a particular
    project and behave as if they are contained in that project.

User management
~~~~~~~~~~~~~~~

Identity user management examples:

* Create a user named ``alice``:

  .. code-block:: console

     $ openstack user create --password-prompt --email alice@example.com alice

* Create a project named ``acme``:

  .. code-block:: console

     $ openstack project create acme --domain default

* Create a domain named ``emea``:

  .. code-block:: console

     $ openstack --os-identity-api-version=3 domain create emea

* Create a role named ``compute-user``:

  .. code-block:: console

     $ openstack role create compute-user

  .. note::

     Individual services assign meaning to roles, typically through
     limiting or granting access to users with the role to the
     operations that the service supports. Role access is typically
     configured in the service's ``policy.yaml`` file. For example,
     to limit Compute access to the ``compute-user`` role, edit the
     Compute service's ``policy.yaml`` file to require this role for
     Compute operations.

The Identity service assigns a project and a role to a user. You might
assign the ``compute-user`` role to the ``alice`` user in the ``acme``
project:

.. code-block:: console

   $ openstack role add --project acme --user alice compute-user

A user can have different roles in different projects. For example, Alice
might also have the ``admin`` role in the ``Cyberdyne`` project. A user
can also have multiple roles in the same project.

The ``/etc/[SERVICE_CODENAME]/policy.yaml`` file controls the
tasks that users can perform for a given service. For example, the
``/etc/nova/policy.yaml`` file specifies the access policy for the
Compute service, the ``/etc/glance/policy.yaml`` file specifies
the access policy for the Image service, and the
``/etc/keystone/policy.yaml`` file specifies the access policy for
the Identity service.

The default ``policy.yaml`` files in the Compute, Identity, and
Image services recognize only the ``admin`` role. Any user with
any role in a project can access all operations that do not require the
``admin`` role.

To restrict users from performing operations in, for example, the
Compute service, you must create a role in the Identity service and
then modify the ``/etc/nova/policy.yaml`` file so that this role
is required for Compute operations.

For example, the following line in the ``/etc/cinder/policy.yaml``
file does not restrict which users can create volumes:

.. code-block:: none

   "volume:create": "",

If the user has any role in a project, he can create volumes in that
project.

To restrict the creation of volumes to users who have the
``compute-user`` role in a particular project, you add ``"role:compute-user"``:

.. code-block:: none

   "volume:create": "role:compute-user",

To restrict all Compute service requests to require this role, the
resulting file looks like:

.. code-block:: json

   {
      "admin_or_owner": "role:admin or project_id:%(project_id)s",
      "default": "rule:admin_or_owner",
      "compute:create": "role:compute-user",
      "compute:create:attach_network": "role:compute-user",
      "compute:create:attach_volume": "role:compute-user",
      "compute:get_all": "role:compute-user",
      "compute:unlock_override": "rule:admin_api",
      "admin_api": "role:admin",
      "compute_extension:accounts": "rule:admin_api",
      "compute_extension:admin_actions": "rule:admin_api",
      "compute_extension:admin_actions:pause": "rule:admin_or_owner",
      "compute_extension:admin_actions:unpause": "rule:admin_or_owner",
      "compute_extension:admin_actions:suspend": "rule:admin_or_owner",
      "compute_extension:admin_actions:resume": "rule:admin_or_owner",
      "compute_extension:admin_actions:lock": "rule:admin_or_owner",
      "compute_extension:admin_actions:unlock": "rule:admin_or_owner",
      "compute_extension:admin_actions:resetNetwork": "rule:admin_api",
      "compute_extension:admin_actions:injectNetworkInfo": "rule:admin_api",
      "compute_extension:admin_actions:createBackup": "rule:admin_or_owner",
      "compute_extension:admin_actions:migrateLive": "rule:admin_api",
      "compute_extension:admin_actions:migrate": "rule:admin_api",
      "compute_extension:aggregates": "rule:admin_api",
      "compute_extension:certificates": "role:compute-user",
      "compute_extension:cloudpipe": "rule:admin_api",
      "compute_extension:console_output": "role:compute-user",
      "compute_extension:consoles": "role:compute-user",
      "compute_extension:createserverext": "role:compute-user",
      "compute_extension:deferred_delete": "role:compute-user",
      "compute_extension:disk_config": "role:compute-user",
      "compute_extension:evacuate": "rule:admin_api",
      "compute_extension:extended_server_attributes": "rule:admin_api",
      "compute_extension:extended_status": "role:compute-user",
      "compute_extension:flavorextradata": "role:compute-user",
      "compute_extension:flavorextraspecs": "role:compute-user",
      "compute_extension:flavormanage": "rule:admin_api",
      "compute_extension:floating_ip_dns": "role:compute-user",
      "compute_extension:floating_ip_pools": "role:compute-user",
      "compute_extension:floating_ips": "role:compute-user",
      "compute_extension:hosts": "rule:admin_api",
      "compute_extension:keypairs": "role:compute-user",
      "compute_extension:multinic": "role:compute-user",
      "compute_extension:networks": "rule:admin_api",
      "compute_extension:quotas": "role:compute-user",
      "compute_extension:rescue": "role:compute-user",
      "compute_extension:security_groups": "role:compute-user",
      "compute_extension:server_action_list": "rule:admin_api",
      "compute_extension:server_diagnostics": "rule:admin_api",
      "compute_extension:simple_tenant_usage:show": "rule:admin_or_owner",
      "compute_extension:simple_tenant_usage:list": "rule:admin_api",
      "compute_extension:users": "rule:admin_api",
      "compute_extension:virtual_interfaces": "role:compute-user",
      "compute_extension:virtual_storage_arrays": "role:compute-user",
      "compute_extension:volumes": "role:compute-user",
      "compute_extension:volume_attachments:index": "role:compute-user",
      "compute_extension:volume_attachments:show": "role:compute-user",
      "compute_extension:volume_attachments:create": "role:compute-user",
      "compute_extension:volume_attachments:delete": "role:compute-user",
      "compute_extension:volumetypes": "role:compute-user",
      "volume:create": "role:compute-user",
      "volume:get_all": "role:compute-user",
      "volume:get_volume_metadata": "role:compute-user",
      "volume:get_snapshot": "role:compute-user",
      "volume:get_all_snapshots": "role:compute-user",
      "network:get_all_networks": "role:compute-user",
      "network:get_network": "role:compute-user",
      "network:delete_network": "role:compute-user",
      "network:disassociate_network": "role:compute-user",
      "network:get_vifs_by_instance": "role:compute-user",
      "network:allocate_for_instance": "role:compute-user",
      "network:deallocate_for_instance": "role:compute-user",
      "network:validate_networks": "role:compute-user",
      "network:get_instance_uuids_by_ip_filter": "role:compute-user",
      "network:get_floating_ip": "role:compute-user",
      "network:get_floating_ip_pools": "role:compute-user",
      "network:get_floating_ip_by_address": "role:compute-user",
      "network:get_floating_ips_by_project": "role:compute-user",
      "network:get_floating_ips_by_fixed_address": "role:compute-user",
      "network:allocate_floating_ip": "role:compute-user",
      "network:deallocate_floating_ip": "role:compute-user",
      "network:associate_floating_ip": "role:compute-user",
      "network:disassociate_floating_ip": "role:compute-user",
      "network:get_fixed_ip": "role:compute-user",
      "network:add_fixed_ip_to_instance": "role:compute-user",
      "network:remove_fixed_ip_from_instance": "role:compute-user",
      "network:add_network_to_project": "role:compute-user",
      "network:get_instance_nw_info": "role:compute-user",
      "network:get_dns_domains": "role:compute-user",
      "network:add_dns_entry": "role:compute-user",
      "network:modify_dns_entry": "role:compute-user",
      "network:delete_dns_entry": "role:compute-user",
      "network:get_dns_entries_by_address": "role:compute-user",
      "network:get_dns_entries_by_name": "role:compute-user",
      "network:create_private_dns_domain": "role:compute-user",
      "network:create_public_dns_domain": "role:compute-user",
      "network:delete_dns_domain": "role:compute-user"
   }

Service management
~~~~~~~~~~~~~~~~~~

The Identity service provides identity, token, catalog, and policy
services. It consists of:

* keystone Web Server Gateway Interface (WSGI) service
    Can be run in a WSGI-capable web server such as Apache httpd to provide
    the Identity service. The service and administrative APIs are run as
    separate instances of the WSGI service.

* Identity service functions
    Each has a pluggable back end that allow different ways to use the
    particular service. Most support standard back ends like LDAP or SQL.

The Identity service also maintains a user that corresponds to each
service, such as, a user named ``nova`` for the Compute service, and a
special service project called ``service``.

For information about how to create services and endpoints, see the
:ref:`Administrator Guide <manage_services>`.

Groups
~~~~~~

A group is a collection of users in a domain. Administrators can
create groups and add users to them. A role can then be assigned to
the group, rather than individual users. Groups were introduced with
the Identity API v3.

Identity API V3 provides the following group-related operations:

* Create a group

* Delete a group

* Update a group (change its name or description)

* Add a user to a group

* Remove a user from a group

* List group members

* List groups for a user

* Assign a role on a project to a group

* Assign a role on a domain to a group

* Query role assignments to groups

.. note::

   The Identity service server might not allow all operations. For
   example, if you use the Identity server with the LDAP Identity
   back end and group updates are disabled, a request to create,
   delete, or update a group fails.

Here are a couple of examples:

* Group A is granted Role A on Project A. If User A is a member of Group
  A, when User A gets a token scoped to Project A, the token also
  includes Role A.

* Group B is granted Role B on Domain B. If User B is a member of
  Group B, when User B gets a token scoped to Domain B, the token also
  includes Role B.
