A two-node Proxmox cluster can lose quorum if either of your hosts fail. This is true even if the server that is left is healthy and its workloads are still run

A two-node Proxmox cluster can lose quorum if either of your hosts fail. This is true even if the server that is left is healthy and its workloads are still running. If Proxmox HA is involved, the HA watchdog service will do what is called self-fencing that can also reset an isolated node to keep it from having split brain in the cluster. I explored how Corosync quorum works, what self-fencing technically does, and how an external QDevice is used. It provides a third vote without requiring another full Proxmox server.