public static void maintainCluster(String destZkString, String destClusterName, boolean enable) {
    HelixZkClient destZkClient = getHelixZkClient(destZkString);
    HelixAdmin destAdmin = new ZKHelixAdmin(destZkClient);
    destAdmin.enableMaintenanceMode(destClusterName, enable);
  }
Enable or disable maintenance mode for a cluster.
@param destZkString the cluster's zk string
@param destClusterName the cluster's name
@param enable enter maintenance mode if true
ambry-commons/src/main/java/com/github/ambry/clustermap/HelixVcrUtil.java