public boolean isCollectorHostLive(String clusterName) {
    if (!externalMetricCollectorsState.isEmpty()) {
      return true;
    }
    MetricsCollectorHAClusterState metricsCollectorHAClusterState = this.clusterCollectorHAState.get(clusterName);
    return metricsCollectorHAClusterState != null && metricsCollectorHAClusterState.isCollectorHostLive();
  }
Handles {@link MetricsCollectorHostDownEvent}

@param event the change event.
ambari-server/src/main/java/org/apache/ambari/server/controller/metrics/MetricsCollectorHAManager.java