Hi, I am able to consistently replicate a case where I get 2 Masters elected in a Singleton service deployed on 2 hosts on the same cluster. This is what I did:
(Using JBoss 3.2.3.)
(1. Started JBOss and the singleton service on a host, say Host A. This becomes the Master.
(2. Started JBoss and the singleton service on another host, say Host B.
(3. Host A is the Master at this point.
(4. I remove the LAN cable and disconnect host A from the network.
(5. Now Host B becomes the Master and host A remains to be the Master. Of course they are not on the same cluster any more since there is no conenctivity from host B to host A.
(6. Now I reconnect the LAN cable to host A to restore connectivity. Host B receives a cluster membership changed event and shows host A as 1 of the members in the cluster.
(7. Host A also shows host B in its list of cluster members, BUT remains to be the Master!
Hence we have 2 masters at this point, both Host A and host B, that are on the same cluster.
I was able to see this problem in JBoss 3.2.3. This problem DOES NOT happen in JBoss 4.0.1 sp1.
Can you please try 3.2.7 then to see if the problem is fixed?