Switch HA Architectures to Percona

Past HA releases have used a Galera implementation from Codership. There is also another popular implementation from Percona. Neither is packaged by Ubuntu in 12.04 LTS. However in Icehouse our base operating system moves to 14.04 LTS, in which Ubuntu has begun packaging Percona XtraDB. This will likely spur some adoption among OpenStack deployments that use Canonical for support, so it probably makes sense for us to evaluate switching to Ubuntu's packaging of XtraDB.

root@trusty-test:~# apt-cache search percona
percona-toolkit - Command-line tools for MySQL and system tasks
percona-xtrabackup - Open source backup tool for InnoDB and XtraDB
percona-xtrabackup-dbg - Debug symbols for Percona XtraBackup
percona-xtrabackup-test - Test suite for Percona XtraBackup
percona-xtradb-cluster-client - Percona XtraDB Cluster database client
percona-xtradb-cluster-client-5.5 - Percona Server database client binaries
percona-xtradb-cluster-common-5.5 - Percona Server database common files
percona-xtradb-cluster-galera-2.x - Synchronous multi-master replication plugin for transactional applications
percona-xtradb-cluster-server - Percona XtraDB Cluster database server
percona-xtradb-cluster-server-5.5 - Percona Server database server binaries
percona-xtradb-cluster-testsuite - Percona XtraDB Cluster database regression test suite
percona-xtradb-cluster-testsuite-5.5 - Percona Server database test suite
xtrabackup - Transitional package for percona-xtrabackup
root@trusty-test:~#

We'll use the whiteboard of this blueprint to evaluate whether the change makes sense and to track progress if we ultimately decide to make the move.