Basically, it's the JGroups coordinator for the jboss:service=DefaultPartition channel, i.e. the first member shown in the "CurrentView" attribute for that mbean [1]. 99% case: JGroups coordinator is the node that's been a member of the cluster the longest. The view is ordered by when nodes joined. 1% case: there was some network disruption and the cluster fell apart into more than one subgroup. Then the disruption ended and the subgroups merged. In that case the view will be ordered based on the IP address / port of the members, so the coordinator will be the one that sorts first. [1] Odd case: you're not using deploy-hasingleton on all nodes in the cluster. In that case, the master will be the first node in the view where deploy-hasingleton is used. Rules for ordering the view are as described above. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4083664#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...