OpenStack uses a SQL database, such as Mysql/MariaDB/Percona, to store information about its services. In the following recipes, we are going to create databases for the Keystone, Glance, Nova, and Neutron projects. We install and configure MariaDB in steps 1 through 3.
The messaging queue we install and configure in step 4 provides a centralized way for the services to communicate with each other by producing and consuming messages. OpenStack supports a few different message bus implementations, such as RabbitMQ, Qpid, and ZeroMQ.
The identity service Keystone caches authentication tokens using the memcached daemon. We install and configure it in step 5.