Sometimes while running LiveCycle on JBoss Cluster, you may see the following log messages appearing in server logs.
WARN [org.jgroups.protocols.UDP] discarded message from different group “DefaultPartition” (our group is “LIVECYCLE-CLUSTER”). Sender was 10.56.78.90:54356
These messages appear due to the collision with other JBoss Clusters within the same network and having the same multicast configuration. If we are running more than one JBoss Cluster with the default or the same multicast configuration (multicast address & port), such collisions may occur due to multicast communication sharing the same multicast address and port.
This scenario can be avoided by maintaining a different multicast configuration for each JBoss cluster. To control the multicast address we can pass -u as command line switch while starting a JBoss server.
Passing this command line argument we can differentiate one cluster from other clusters.
Note: Each JBoss instance belonging to the same cluster should use the same multicast address.