protected String getClientHostForRunningAction(Cluster cluster, Service service, ServiceComponent serviceComponent)
      throws AmbariException {
    if (serviceComponent != null && !serviceComponent.getServiceComponentHosts().isEmpty()) {
      Set<String> candidateHosts = serviceComponent.getServiceComponentHosts().keySet();
      filterHostsForAction(candidateHosts, service, cluster, Resource.Type.Cluster);
      return getHealthyHost(candidateHosts);
    }
    return null;
  }
Get a request response for the given request ids.  Note that this method
fully populates a request resource including the set of task sub-resources
in the request response.
ambari-server/src/main/java/org/apache/ambari/server/controller/AmbariManagementControllerImpl.java