About Keystone
All users and services rely on Keystone. Without Keystone, users would not have the ability to properly authenticate and create virtual machines, networks, and other resources. OpenStack services would not be able to properly authenticate in order to successfully fulfill user requests, or to make requests to other OpenStack services.
Authentication or authorization?
Before we begin to dive into the details of Keystone, let's take a moment to think about the concepts of authentication and authorization. These two words are sometimes misused, so let's provide a proper definition.
Authentication is the act of confirming the identity of a specific user—in other words, proving that a user is whom she or he claims to be.
Authorization is the function of determining access rights for that specific user.
Keystone has a variety of functions, but first and foremost, it provides authentication. All OpenStack users are required to authenticate to Keystone via the Horizon dashboard, command...