Please describe exactly how you are deploying your singleton. I can guess from what you wrote, but I want to be sure. My guess is that you packaged your singleton code in a sar and in the sar's jboss-service.xml included an mbean for your service and an mbean for an HASingletonController to control your service. Then you deployed the sar in deploy/ on A and B. If that's what you did, it should work the way you want, and if it doesn't we need to investigate why not. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4106776#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...