Identity concepts

Identity concepts

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

    $ openstack user create --password-prompt --email alice
  • Create a project named acme:

    $ openstack project create acme --domain default
  • Create a domain named emea:

    $ openstack --os-identity-api-version=3 domain create emea
  • Create a role named compute-user:

    $ openstack role create compute-user


    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.json file. For example, to limit Compute access to the compute-user role, edit the Compute service’s policy.json 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:

$ 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.json file controls the tasks that users can perform for a given service. For example, the /etc/nova/policy.json file specifies the access policy for the Compute service, the /etc/glance/policy.json file specifies the access policy for the Image service, and the /etc/keystone/policy.json file specifies the access policy for the Identity service.

The default policy.json 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.json file so that this role is required for Compute operations.

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

"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":

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

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

   "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.
  • keystone-all
    Starts both the service and administrative APIs in a single process. Using federation with keystone-all is not supported. keystone-all is deprecated in favor of the WSGI service. Also, this will be removed in Newton.

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 OpenStack Administrator Guide.


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


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.
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