code: func ValidateReplicationControllerStatusUpdate(controller, oldController *api.ReplicationController) field.ErrorList {
  	allErrs := ValidateObjectMetaUpdate(&controller.ObjectMeta, &oldController.ObjectMeta, field.NewPath("metadata"))
  	statusPath := field.NewPath("status")
  	allErrs = append(allErrs, ValidatePositiveField(int64(controller.Status.Replicas), statusPath.Child("replicas"))...)
  	allErrs = append(allErrs, ValidatePositiveField(int64(controller.Status.ObservedGeneration), statusPath.Child("observedGeneration"))...)
  	return allErrs
  }
docs: // ValidateReplicationControllerStatusUpdate tests if required fields in the replication controller are set.