Pacemaker/Corosync is a good tool if you know exactly how it works. However, very few people know exactly how it works. This is a very old problem for that team

Pacemaker/Corosync is a good tool if you know exactly how it works. However, very few people know exactly how it works. This is a very old problem for that team if you check the mailing lists. If they offered a few "blessed" configurations or even an online config generator, I'm sure that people would have nicer things to say about it. I've used it heartbeat/pacemaker/corosync with DRBD for over a decade and I'm pretty pleased with it...now. But it took a bit of trial by fire to get it right. Luckily I never lost any data and found the issues in testing. Which gets at the heart of any failover mechanism -- it's all useless unless you test it on a regular basis (just like your backups).