[Linux-cluster] Minimal requirements for two nodes to see eachother

[Jure Pečar]

Hi all,

I'm setting up a simple two node cluster over a shared storage. I want to
use gfs, but I'm hitting some problems much earlier. 

After setting up the basics with system-config-cluster and starting up
ccsd, cman and rgmanager on both nodes, clustat says 

on node1:

Member Status: Quorate

  Member Name                              Status
  ------ ----                              ------
  node1                                    Online, Local, rgmanager
  node2                                    Offline

  Service Name         Owner (Last)                   State         
  ------- ----         ----- ------                   -----         
  http_test            node1                          started         



and on node2:

Member Status: Quorate

  Member Name                              Status
  ------ ----                              ------
  node1                                    Offline
  node2                                    Online, Local, rgmanager

  Service Name         Owner (Last)                   State         
  ------- ----         ----- ------                   -----         
  http_test            node2                          started         


For some reason nodes don't see eachother, which results in the above
situation. I guess the same reason causes fence_tool join -w to wait
forever, which on boot appears as a hung machine (a bit ugly, because
fenced is started before sshd by default). Both nodes have their info
in /etc/hosts as well as in DNS and network connectivity is OK.

As the documentation is not much helpful with how to figure this out, I'm
asking it here: what minimal requirements must be met for two machines to
see eachother? How to debug a situation like this?


-- 

Jure Pečar
http://jure.pecar.org/