[Pacemaker] node is offline; can't bring online

[Paul Archer]

I'm fairly new to pacemaker, and this is hurting my head.
I have a four-node cluster, and one of my nodes (for no reason that I
can discern) has gone offline, and I can't get it to come back online.

Offline node:
root at vmhost2:/var/lib/heartbeat# crm_mon -1
============
Last updated: Wed Nov  7 20:52:16 2012
Last change: Wed Nov  7 20:28:06 2012 via cibadmin on vmhost2
Stack: openais
Current DC: NONE
4 Nodes configured, 4 expected votes
7 Resources configured.
============

OFFLINE: [ vgs1 vgs2 vmhost1 vmhost2 ]



One of the online nodes:
root at vmhost1:/var/lib/heartbeat/crm# crm_mon -1
============
Last updated: Wed Nov  7 20:45:32 2012
Last change: Wed Nov  7 20:44:59 2012 via crm_attribute on vgs2
Stack: openais
Current DC: vgs1 - partition with quorum
Version: 1.1.6-9971ebba4494012a93c03b40a2c58ec0eb60f50c
4 Nodes configured, 4 expected votes
7 Resources configured.
============

Node vmhost2: standby
Online: [ vgs1 vgs2 vmhost1 ]

 focus  (ocf::heartbeat:VirtualDomain): Started vmhost1
 logger (ocf::heartbeat:VirtualDomain): Started vmhost1
 mother (ocf::heartbeat:VirtualDomain): Started vmhost2
 vgsIP  (ocf::heartbeat:IPaddr2):       Started vgs2
 vgsWebServer   (ocf::heartbeat:apache):        Started vgs2


I don't know what's relevant as far as log files, so I will post as
people ask for specifics, rather than just dumping everything here to
start with.


Thanks for any help,

Paul