@Override
    public void transition(ServiceComponentHostImpl impl,
        ServiceComponentHostEvent event) {
      // TODO Audit logs
      impl.updateLastOpInfo(event.getType(), event.getOpTimestamp());

    }
The name of the host (which should never, ever change)
ambari-server/src/main/java/org/apache/ambari/server/state/svccomphost/ServiceComponentHostImpl.java