The Identity Service provides identity, token, catalog, and policy services. It consists of:
keystone-all. Starts both the service and administrative APIs in a single process to provide Catalog, Authorization, and Authentication services for OpenStack.Identity Service functions. Each has a pluggable back end that allows 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 tenant called service.
For information about how to create services and endpoints, see the OpenStack Admin User Guide.
