private String getSeniorMember() {
        return ClusterManager.getNodeInfo(ClusterManager.getSeniorClusterMember()).map(ClusterNodeInfo::getHostName).orElse(UNKNOWN_NODE_NAME);
    }
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