It is important to make available some kind of a database as a service inside the cluster. Many other services like Keycloak for example rely on a pre-existing database service that must be configured during the installation. Otherwise keycloak will use default storage backed which was file based and only for development purposes. The following DBs are supported by keycloak
Certs are generated inside pod in /var/lib/mysql automatically but can be replaced if needed.
-rw-r----- 1 mysql mysql 56 Jun 14 15:44 auto.cnf