public void enqueueAgentCommands(long clusterId, Collection<String> hosts) {
    String clusterName = null;
    Cluster cluster = null;

    try {
      cluster = m_clusters.get().getClusterById(clusterId);
      clusterName = cluster.getClusterName();
    } catch (AmbariException ae) {
      LOG.error("Unable to lookup cluster for alert definition commands", ae);
    }

    enqueueAgentCommands(cluster, clusterName, hosts);
  }
Enqueue {@link AlertDefinitionCommand}s for every host specified so that
they will receive a payload of alert definitions that they should be
running.
<p/>
This method is typically called after
{@link #invalidateHosts(AlertDefinitionEntity)} has caused a cache
invalidation of the alert definition hash.

@param clusterId
         the ID of the cluster.
@param hosts
         the hosts to push {@link AlertDefinitionCommand}s for.
ambari-server/src/main/java/org/apache/ambari/server/state/alert/AlertDefinitionHash.java