I've gotten a prototype version of deploy-hasingleton functionality to work with the new SPI. Fundamental classes are: http://anonsvn.jboss.org/repos/jbossas/trunk/cluster/src/main/org/jboss/h... http://anonsvn.jboss.org/repos/jbossas/trunk/cluster/src/main/org/jboss/h... The HASingletonProfileActivator is configured with the strings necessary to make up a ProfileKey and a ref to the ProfileService. It then exposes methods an HASingletonController can invoke when it becomes/stops being the master. Those methods call ProfileService.activateProfile() and releaseProfile(). The HASingletonProfileManager is a subclass that takes a List as a configuration element and uses that to create a Profile for the deploy-hasingleton content. I'll post separately about why I think this is wrong. This code is committed but not used yet because making it work requires a change to AbstractProfileService that I want to discuss before committing. Will post separately on that as well. Some comments on the SPI: 1) Should "public void registerProfile(Profile profile)" instead be "public void registerProfile(ProfileMetaData profile)"? Let the ProfileService handle creation of the Profile from metadata. To make my HASingletonProfileManager work I needed to inject a reference to the ProfileFactory bean, which smells wrong. 2) Similar thing with "public void unregisterProfile(Profile profile)". I think the argument should be a ProfileKey. 3) This is just a nit. Why releaseProfile(ProfileKey key) instead of inactivateProfile(ProfileKey key)? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4204451#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...