After a cold boot, the leader has likely changed. Do not add this node
as a former leader to the hosts list. This may cause changes to
mysqld.cnf and an unwanted attempted restart of mysql.
Ensure ocf file is installed early so that mysql monitor resource can
start as soon as it is defined. Otherwise it will be down and may
not come backup without manual intervention.
Using DDL for the root password update triggers the cluster to
replicate the password rather than relying on the charm to apply it
to each unit. This means that only the leader should update the
password.
To avoid a password update via config being missed the implicit save
of config data is turned off on update-status hooks.
Configure pacemaker to never give up on the res_mysql_monitor
resource and to recheck 5 seconds after a failure. This is
achieved using migration-threshold and failure-timeout
options *1.
