Slight qualification to the above: in 4.0.x the master for an HASingleton service is the cluster member that: 1) Has the service deployed. 2) Holds the lowest position in the cluster view, which is usually ordered by when nodes joined the cluster. If the typical case where all the nodes in the cluster have the service deployed, the JGroups coordinator is the master. The JGroups coordinator always has the lowest (i.e first) position in the view. This is also the default behavior in 4.2.x, although the pluggable policies I mentioned let you change that. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4046618#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...