Cause: The galera resource agent is only able to connect to a local MariaDB socket.
Consequence: The resource agent can fail due to uncontrolled
events, like for instance max connection reached, or slow connections (e.g. when mariadb threadpool is engaged).
Fix: Add support for custom host/port options, in order
to benefit from MariaDB's extra-port and extra-max-connections.
Result: Able to connect to other MariaDB resources.