Summary
In this chapter, we have explained how to monitor, troubleshoot, and fix common cluster problems and needs. Not all of these will be undesired or unexpected as a sudden system crash. There will be times when you need to bring down the cluster and the resources it is running for some planned maintenance or during a power outage before your uninterruptible power supply (UPS) runs out.
Because prevention is your best ally in these circumstances, ensure that you routinely monitor the health of your cluster. Follow the procedures outlined in this chapter so that you don't run into any surprises when real emergencies come up. Specifically, under either real or simulated cases, ensure that you back up the cluster configuration, stop the cluster on both nodes separately, and then and only then, halt the node.
