If at any time all of the nodes in your cluster have been taken down, it is necessary to re-initialize the Galera replication state. In effect, this is identical to bootstrapping the cluster.

Start by manually bringing up the cluster IP on one of your nodes:

ip address add 192 …

Now you can proceed with setting Galera specifics in your MySQL configurations.

Create a configuration file, identical on all cluster nodes, named /etc/mysql/conf.d/galera.cnf with the following content:

[mysqld]
bind_address=0.0.0.0
binlog_format=ROW
default_storage_engine=InnoDB
innodb_autoinc_lock_mode=2
innodb_locks_unsafe_for_binlog=1

Create another configuration file …

Once Corosync is running, you are able to start the Pacemaker cluster resource manager on all cluster nodes:

service pacemaker start

Once cluster startup is completed, you should see output similar to the following when invoking the crm_mon utility:

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Last updated: Mon Dec  3 15:37:59 2012
Last change …

If MySQL happens to die in your cluster, Pacemaker will automatically recover the service in place. To test this, select any node on your cluster and send the mysqld process a KILL signal:

killall -KILL mysqld

Then, monitor your cluster status with crm_mon -rf. After a few seconds, you should …

This is a tutorial that Yves Trudeau and I presented at the Percona Live UK 2012 conference in London. It covers Pacemaker integration with DRBD, MySQL Replication, and Galera.