Keystone tokens¶

Unscoped tokens¶

An unscoped token contains neither a service catalog, any roles, a project scope, nor a domain scope. Their primary use case is simply to prove your identity to keystone at a later time (usually to generate scoped tokens), without repeatedly presenting your original credentials.

The following conditions must be met to receive an unscoped token:

• You must not specify an authorization scope in your authentication request (for example, on the command line with arguments such as --os-project-name or --os-domain-id),
• Your identity must not have a “default project” associated with it that you also have role assignments, and thus authorization, upon.

Project-scoped tokens¶

Project-scoped tokens are the bread and butter of OpenStack. They express your authorization to operate in a specific tenancy of the cloud and are useful to authenticate yourself when working with most other services.

They contain a service catalog, a set of roles, and details of the project upon which you have authorization.

Domain-scoped tokens¶

Domain-scoped tokens also have limited use cases in OpenStack. They express your authorization to operate a domain-level, above that of the user and projects contained therein (typically as a domain-level administrator). Depending on Keystone’s configuration, they are useful for working with a single domain in Keystone.

They contain a limited service catalog (only those services which do not explicitly require per-project endpoints), a set of roles, and details of the project upon which you have authorization.

They can also be used to work with domain-level concerns in other services, such as to configure domain-wide quotas that apply to all users or projects in a specific domain.

UUID tokens¶

UUID was the first token type supported and is currently the default token provider. UUID tokens are 32 bytes in length and must be persisted in a back end. Clients must pass their UUID token to the Identity service in order to validate it.

As mentioned above, UUID tokens must be persisted. By default, keystone persists UUID tokens using a SQL backend. An unfortunate side-effect is that the size of the database will grow over time regardless of the token’s expiration time. Expired UUID tokens can be pruned from the backend using keystone’s command line utility:

$ keystone-manage token_flush

We recommend invoking this command periodically using cron.

Fernet tokens¶

The fernet token format was introduced in the OpenStack Kilo release. Unlike the other token types mentioned in this document, fernet tokens do not need to be persisted in a back end. AES256 encryption is used to protect the information stored in the token and integrity is verified with a SHA256 HMAC signature. Only the Identity service should have access to the keys used to encrypt and decrypt fernet tokens. Like UUID tokens, fernet tokens must be passed back to the Identity service in order to validate them. For more information on the fernet token type, see the Fernet - Frequently Asked Questions.

PKI and PKIZ tokens¶

PKI tokens are signed documents that contain the authentication context, as well as the service catalog. Depending on the size of the OpenStack deployment, these tokens can be very long. The Identity service uses public/private key pairs and certificates in order to create and validate PKI tokens.

The same concepts from PKI tokens apply to PKIZ tokens. The only difference between the two is PKIZ tokens are compressed to help mitigate the size issues of PKI. For more information on the certificate setup for PKI and PKIZ tokens, see the Certificates for PKI.