stallIfBackupMaster(this.conf, this.activeMasterManager);
// The ClusterStatusTracker is setup before the other
// ZKBasedSystemTrackers because it's needed by the activeMasterManager
// to check if the cluster should be shutdown.
this.clusterStatusTracker = new ClusterStatusTracker(getZooKeeper(), this);
this.clusterStatusTracker.start();
return this.activeMasterManager.blockUntilBecomingActiveMaster(startupStatus,
this.clusterStatusTracker);
}