message IPAddressSpec {
  // ParentRef references the resource that an IPAddress is attached to.
  // An IPAddress must reference a parent object.
  // +required
  optional ParentReference parentRef = 1;
}

// ParentReference describes a reference to a parent object.
message ParentReference {
  // Group is the group of the object being referenced.
  // +optional
  optional string group = 1;

  // This value will be null if an APIService reports subresources but supports no operations on the parent resource
  optional k8s.io.apimachinery.pkg.apis.meta.v1.GroupVersionKind responseKind = 2;

  // scope indicates the scope of a resource, either Cluster or Namespaced
  optional string scope = 3;