@Override
    public void leftCluster() {
        final String nodeName = xmppServer.getServerInfo().getHostname();
        LOGGER.info("This node ({}/{}) has left the cluster", xmppServer.getNodeID(), nodeName);
        sendMessageToAdminsIfEnabled("The local node ('" + nodeName + "') has left the cluster - this node no longer has any resilience");
    }
Monitors the state of the cluster, and warns admins when nodes leave or rejoin the cluster
xmppserver/src/main/java/org/jivesoftware/openfire/cluster/ClusterMonitor.java