If your consensus protocol requires that it is probably broken. If you can't rely on a node to shut itself down then you almost certainly can't rely on an external trigger to do it. Paxos, raft, etc work just fine as long as failures are non-byzantine. Achieving non-byzantine failures is definitely not always possible (e.g. someone hacking your server and reprogramming it to subvert the protocol) but checksums on disk and network go most of the way.
