Fencing question


think of a three node cluster Node1, Node2 and Node3

Does fencing work (and how) if only Node1 can communicate to Node2 and Node3, while the communication between Node2 and Node3 is broken completely ?


I can not figure out how that could happen but feel free to contradict me

  1. All three nodes are on the same lan, they must be
  2. For any node to communicate with anything else on the network the node’s nic must work, arp must work and ip must work on both that node and the other end
  3. If node1 can not communicate over the lan with node2 and everything is good with node1 I can not see how node3 could communicate with node2 either. If something lan related and connected to node2 has failed there will be no lan comms with node2 to anything. E.g switch port, nic, cable, ip stack, system crashed, lan driver hung … etc.
  4. If someone had added a duplicate ip address to say node2 it will shut down its network interface, again no lan comms with node1 or node3
    I can not see a scenario where this could happen.

I am missing something??