implement field selector for clusterIP on services

This will allow components that don't need to watch headless services
(heavily used on ai/ml workloads) to filter them server side.

Specially useful for kubelet and kube-proxy

Co-authored-by: Jianbo Ma <sakuranlbj@gmail.com>

Change-Id: I6434d2c8c77aaf725ec5c07acbcda14311f24bfa

Change-Id: Iba9e25afb90712facfb3dee25c500bbe08ef38fc

pkg/apis/core/v1/conversion.go

@@ -97,6 +97,9 @@ func addConversionFuncs(scheme *runtime.Scheme) error {
 	if err := AddFieldLabelConversionsForSecret(scheme); err != nil {
 		return err
 	}
+	if err := AddFieldLabelConversionsForService(scheme); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -488,6 +491,20 @@ func AddFieldLabelConversionsForSecret(scheme *runtime.Scheme) error {
 		})
 }
 
+func AddFieldLabelConversionsForService(scheme *runtime.Scheme) error {
+	return scheme.AddFieldLabelConversionFunc(SchemeGroupVersion.WithKind("Service"),
+		func(label, value string) (string, string, error) {
+			switch label {
+			case "metadata.namespace",
+				"metadata.name",
+				"spec.clusterIP":
+				return label, value, nil
+			default:
+				return "", "", fmt.Errorf("field label not supported: %s", label)
+			}
+		})
+}
+
 var initContainerAnnotations = map[string]bool{
 	"pod.beta.kubernetes.io/init-containers":          true,
 	"pod.alpha.kubernetes.io/init-containers":         true,