Have you tried shooting a node in the head and seeing what happens? Always a good exercise to run. Run a few disaster recovery exercises and see if you can get it back. I recommend doing that on non-production of course!
Thanks for the tip. I did yesterday actually by manually shutting down the node from SSH (sudo shutdown). It seemed to "just work" without having to do anything else. There might have been a tiny period of unavailability to one of my services but not enough for me to notice. Luckily, I don't have crazy high availability requirements yet.