Merge pull request #712 from feiskyer/cherry-0.7

cherry-pick of #703 to 0.7: Provide IPv6 support for internal load balancer

pkg/provider/azure_loadbalancer.go

@@ -1738,13 +1738,6 @@ func (az *Cloud) reconcileFrontendIPConfigs(clusterName string, service *v1.Serv
 			// construct FrontendIPConfigurationPropertiesFormat
 			var fipConfigurationProperties *network.FrontendIPConfigurationPropertiesFormat
 			if isInternal {
-				// azure does not support ILB for IPv6 yet.
-				// TODO: remove this check when ILB supports IPv6 *and* the SDK
-				// have been rev'ed to 2019* version
-				if utilnet.IsIPv6String(service.Spec.ClusterIP) {
-					return nil, false, fmt.Errorf("ensure(%s): lb(%s) - internal load balancers does not support IPv6", serviceName, lbName)
-				}
-
 				subnetName := subnet(service)
 				if subnetName == nil {
 					subnetName = &az.SubnetName
@@ -1762,6 +1755,10 @@ func (az *Cloud) reconcileFrontendIPConfigs(clusterName string, service *v1.Serv
 					Subnet: &subnet,
 				}
 
+				if utilnet.IsIPv6String(service.Spec.ClusterIP) {
+					configProperties.PrivateIPAddressVersion = network.IPv6
+				}
+
 				loadBalancerIP := service.Spec.LoadBalancerIP
 				if loadBalancerIP != "" {
 					configProperties.PrivateIPAllocationMethod = network.Static