// probeHostname returns the correct localhost IP address family based on the endpoint AdvertiseAddress
	probeHostname, probePort, probeScheme := staticpodutil.GetEtcdProbeEndpoint(&cfg.Etcd, utilsnet.IsIPv6String(endpoint.AdvertiseAddress))
	return staticpodutil.ComponentPod(
		v1.Container{
			Name:            kubeadmconstants.Etcd,
			Command:         getEtcdCommand(cfg, endpoint, nodeName, initialCluster),

		if len(service.Spec.ClusterIP) == 0 || service.Spec.ClusterIP == v1.ClusterIPNone {
			return ""
		}

		IsIPv6Family := (ipFamily == v1.IPv6Protocol)
		if IsIPv6Family == netutils.IsIPv6String(service.Spec.ClusterIP) {
			return service.Spec.ClusterIP
		}

		return ""
	}

	for idx, family := range service.Spec.IPFamilies {
		if family == ipFamily {

	}

	return nil, false, fmt.Errorf("Spec does not reference a NFS volume type")
}

func getServerFromSource(source *v1.NFSVolumeSource) string {
	if netutil.IsIPv6String(source.Server) {
		return fmt.Sprintf("[%s]", source.Server)
	}
	return source.Server

			// upgrade is completed (controller connects to api-server that correctly defaults services)
			if utilnet.IsIPv6String(pod.Status.PodIP) {
				ipFamily = v1.IPv6Protocol
			}
		}
	}

	// find an ip that matches the family
	for _, podIP := range pod.Status.PodIPs {
		if (ipFamily == v1.IPv6Protocol) == utilnet.IsIPv6String(podIP.IP) {
			endpointIP = podIP.IP
			break
		}
	}

	if endpointIP == "" {

			continue
		}

		// Filter out the incorrect IP version case. Any endpoint port that
		// contains incorrect IP version will be ignored.
		if (cache.ipFamily == v1.IPv6Protocol) != utilnet.IsIPv6String(endpoint.Addresses[0]) {
			// Emit event on the corresponding service which had a different IP
			// version than the endpoint.

	r.muTree.Lock()
	defer r.muTree.Unlock()
	r.tree = tree
	return nil
}

func newIPAddress(name string, svc *v1.Service) *networkingv1alpha1.IPAddress {
	family := string(v1.IPv4Protocol)
	if netutils.IsIPv6String(name) {
		family = string(v1.IPv6Protocol)
	}
	return &networkingv1alpha1.IPAddress{
		ObjectMeta: metav1.ObjectMeta{
			Name: name,
			Labels: map[string]string{

		// duplicate containerPort / protocol rules work across different address families.
		// https://github.com/kubernetes/kubernetes/issues/82373
		family := "any"
		if p.HostIP != "" {
			if utilsnet.IsIPv6String(p.HostIP) {
				family = "v6"
			} else {
				family = "v4"
			}
		}

		var name = p.Name
		if name == "" {

		}
	} else {
		// Headful: init ipFamilies from clusterIPs.
		service.Spec.IPFamilies = make([]api.IPFamily, len(service.Spec.ClusterIPs))
		for idx, ip := range service.Spec.ClusterIPs {
			if netutil.IsIPv6String(ip) {
				service.Spec.IPFamilies[idx] = api.IPv6Protocol
			} else {
				service.Spec.IPFamilies[idx] = api.IPv4Protocol
			}
		}
		if len(service.Spec.IPFamilies) == 1 {

func (hst HTTPProxyCheck) Check() (warnings, errorList []error) {
	klog.V(1).Infoln("validating if the connectivity type is via proxy or direct")
	u := &url.URL{Scheme: hst.Proto, Host: hst.Host}
	if netutils.IsIPv6String(hst.Host) {
		u.Host = net.JoinHostPort(hst.Host, "1234")
	}

	req, err := http.NewRequest("GET", u.String(), nil)
	if err != nil {
		return nil, []error{err}
	}

	var validPrimaryIP, validSecondaryIP func(ip string) bool
	if len(kl.nodeIPs) == 0 || utilnet.IsIPv4(kl.nodeIPs[0]) {
		validPrimaryIP = utilnet.IsIPv4String
		validSecondaryIP = utilnet.IsIPv6String
	} else {
		validPrimaryIP = utilnet.IsIPv6String
		validSecondaryIP = utilnet.IsIPv4String
	}
	for _, ip := range podIPs {
		if validPrimaryIP(ip) {
			ips = append(ips, ip)
			break
		}
	}