ResourceInstance createClusterResource(String clusterName) {
    return createResource(Resource.Type.Cluster,
        Collections.singletonMap(Resource.Type.Cluster, clusterName));
  }
Create a cluster resource instance.

@param clusterName cluster name

@return a cluster resource instance
ambari-server/src/main/java/org/apache/ambari/server/api/services/ClusterService.java