code: func ValidateDaemonSetUpdate(controller, oldController *extensions.DaemonSet) field.ErrorList {
  	allErrs := apivalidation.ValidateObjectMetaUpdate(&controller.ObjectMeta, &oldController.ObjectMeta, field.NewPath("metadata"))
  	allErrs = append(allErrs, ValidateDaemonSetSpec(&controller.Spec, field.NewPath("spec"))...)
  	allErrs = append(allErrs, ValidateDaemonSetTemplateUpdate(controller.Spec.Template, oldController.Spec.Template, field.NewPath("spec", "template"))...)
  	return allErrs
  }
docs: // ValidateDaemonSetUpdate tests if required fields in the DaemonSet are set.