When we call crm resource migrate, Pacemaker merely makes a simple configuration change. As the PGServer resource is running on pg1 and we set stickiness to 100, any score higher than that will override the current (and preferred) node.
When we ask for a migration, Pacemaker sets the node score for pg2 at the highest value possible. The next time the resource target evaluation system runs, it sees that the score has changed and starts reorganizing the cluster to match. It's actually quite elegant. Unfortunately, it means that we need to remove the score, or we could be in trouble later.
When we unmigrate the PGServer group, Pacemaker removes the infinite score assigned to pg2, leaving it with the regular score of 100. This ...
