Users can participate in numerous projects.
Tenant refers to a group of users as well as an alternate name for project/accounts in cloud processing, where projects are organizational units.
A user’s role is the position to which they are assigned (the authorization level). Project-user duos are generally allocated roles.
The most essential and recommended Identity Service in OpenStack is Keystone, which implements the whole OpenStack Identity API. User administration and the service catalogue are handled by the Keystone Identity Service. It records users and their rights in user management, whereas the Service Catalog provides a catalogue of services that may be accessed through their API. The former contains information on users, tenants, and roles’ authentication credentials.
Keystone Identity additionally includes internal services such as Token and Policy.