@Override
    public void deconstruct() {
        if (controller != null) controller.countdown(options.clusterName());
    }
The {@link VespaZooKeeperServer} argument is required by the injected {@link ClusterController},
to ensure that zookeeper has started before it starts polling it. It must be done here to avoid
duplicates being created by the dependency injection framework.
clustercontroller-apps/src/main/java/com/yahoo/vespa/clustercontroller/apps/clustercontroller/ClusterControllerClusterConfigurer.java