Keystone - identity service

Keystone handles authentication. It acts as a common authentication system across all core services in an OpenStack environment. Both human users and services must authenticate to Keystone to retrieve a token before interacting with other services in the environment.

Visualize the process of logging on to a website with your username and password. When a user does this on the Horizon dashboard, they authenticate against Keystone to successfully login and begin creating virtual resources. Keystone also stores the service catalog, users, domains, projects, groups, roles, and quotas—exam objective concepts you'll examine in Chapter 3, Keystone Identity Service.