ha cluster order

This is my situation: -I have 5 nodes in 1 cluster. ( Node 1, Node 2, Node 3, Node 4, Node 5) 1-Now i want to migrate (Node 1 <-> Node 4, Node 2 <-> Node 3) if 1 node fail. Does it possible ? I know the priority is used but just 1 node or more 2 nodes with same priority, not the permanent one...

I'm testing VM HA in a 4 nodes Ceph Cluster. I See "Use Watchdog base Fancing". I Have 4 Supermicro, is it better if i configure IPMI Fencing ? Thanks

We have a NFS server and a DB server in HA mode as services to offer to others VMs. It's true that in a HA cluster the order option it's not used ? At cluster start the HA VMs take precedence before others ? (we had this week a situation that needs to restart the cluster) We need our NFS and DB...