As we have seen throughout this book, many OpenStack services make heavy use of databases. Production deployments typically use MySQL or Postgres as a backend database server. As you have learned, a failing or misconfigured database will quickly lead to trouble in your OpenStack cluster. Database problems can also present more subtle concerns that may grow into huge problems if neglected.
The database server can become a single point of failure if your database server is not deployed in a highly available configuration. OpenStack does not require a high-availability installation of your database, and as a result, many installations may skip this step. However, production deployments of OpenStack should take care to ensure that their database can survive the failure of a single database server.