code: func ValidatePodTemplateUpdate(newPod, oldPod *core.PodTemplate) field.ErrorList {
  	allErrs := ValidateObjectMetaUpdate(&newPod.ObjectMeta, &oldPod.ObjectMeta, field.NewPath("metadata"))
  	allErrs = append(allErrs, ValidatePodTemplateSpec(&newPod.Template, field.NewPath("template"))...)
  	return allErrs
  }
docs: // ValidatePodTemplateUpdate tests to see if the update is legal for an end user to make. newPod is updated with fields
  // that cannot be changed.