server does not recognize cluster

[bentins]

I have a two server JBoss 4.2.3 cluster set up which worked fine for more then three years. Recently we have moved the servers to a new network. After fixing all the IP's and hostnames in the configuration files I've turned on the servers. Server one comes up fine. Server two starts up but doesn't recognize the cluster and thinks his alone on the cluster. After some time it suddently does recognize the other machine but still thinks he is master. Since I have processes running as ha-singleton which should only run on one machine this is a problem.

Some times, when I restart the second jboss it finds the cluster on start and everything is fine. Can anyone think of reasons which can cause this behavior? Should I try a different multicast address for the groups mechanism?

Thnx

[rhusar]

There might be an issue in 4.2 that singletons continue to run after merge, there was same issue in 5.1, see https://issues.jboss.org/browse/JBPAPP-6932

Why clusters dont connect up, only reason I can think of is that there is an issue with the network, something wrong with multicasting. You can use a different discovery protocol if UDP and multicasting is a problem for you.

HTH,

Rado

[wdfink]

You should check the multicast with this tools [1,2]

If there are lost messages for the MCast test [2] it will be an indicator for network problems.

It is possible that the configuration or the network hardware is the problem.

[1] http://community.jboss.org/wiki/TestingJBoss

[2] http://www.jgroups.org/manual/html/ch02.html see '2.8. It doesn't work'