@ApiModelProperty(name = ClusterResourceProvider.DESIRED_SERVICE_CONFIG_VERSIONS)
  public ServiceConfigVersionRequest getServiceConfigVersionRequest() {
    return serviceConfigVersionRequest;
  }
Gets any configuration-based request (if any).
@return the list of configuration requests,
or <code>null</code> if none is set.
ambari-server/src/main/java/org/apache/ambari/server/controller/ClusterRequest.java