The Cpanel team has published this presentation from their training similar that addresses how to use remote MySQL servers and the basics of MySQL clustering and replication:

http://trainingseminar.cpanel.net/slides/trackb/MySQL%20Remote%20Server.pdf

Cpanel’s support for remote MySQL servers is not very robust, but most web hosts should consider it if they are running highly dense shared hosting servers. The presentation outlines the modifications necessary to point Cpanel and its related applications to the remote MySQL server.