Now that we have a working Pacemaker cluster-management system, we should put it to use. There are a lot of scenarios where we might need to manually change the active PostgreSQL node. Doing this with Pacemaker is much easier than the process we outlined in the previous chapter. That was a long process composed of several manual steps, each of which we would want to confirm in a perfect world.
With Pacemaker, we can change the active system by issuing a single command from any node in the cluster. There are some safeguards we'll also need to discuss and possibly a caveat or two to consider, but this will be our first use of Pacemaker as a piece of functional software. We've done a lot of work setting everything up!
Let's make Pacemaker do some work on our behalf for a change.