Up-voting you because, well, everyone always forgets about Corosync. About the only criticism one could have had about it was that when it only supported multic

Up-voting you because, well, everyone always forgets about Corosync. About the only criticism one could have had about it was that when it only supported multicast you couldn't use it with EC2 and other providers that (for good reason) blocked multicast. It now can do UDPU so it works on EC2. The other great thing about corosync+pacemaker is that it's super easy to write your own HA scripts. Need mongodb? Then write your own script(not sure why you'd use corosync for this, but you could...).