Remove enforcement of IPv6 LB as internal (kubernetes#2557)

In OpenStack IPv6 that uses GUAs don't require NAT
to access the outside world, so IPv6 can be
rechable without Floating IPs, which makes the
enforcement of IPv6 LB as internal in CPO not necessary.
This commit removes this enforcement, which results in
IPv6 load-balancers being allowed to be shared between
Services. Also, now it's possible to make the load-balancer
use the IPv6 stateful address defined in the loadBalancerIP
of the Service.

Author: MaysaMacedo

pkg/openstack/events.go

@@ -21,4 +21,5 @@ const (
 	eventLBExternalNetworkSearchFailed = "LoadBalancerExternalNetworkSearchFailed"
 	eventLBSourceRangesIgnored         = "LoadBalancerSourceRangesIgnored"
 	eventLBAZIgnored                   = "LoadBalancerAvailabilityZonesIgnored"
+	eventLBFloatingIPSkipped           = "LoadBalancerFloatingIPSkipped"
 )

pkg/openstack/loadbalancer.go

@@ -259,8 +259,10 @@ func (lbaas *LbaasV2) createOctaviaLoadBalancer(name, clusterName string, servic
 
 	// For external load balancer, the LoadBalancerIP is a public IP address.
 	loadBalancerIP := service.Spec.LoadBalancerIP
-	if loadBalancerIP != "" && svcConf.internal {
-		createOpts.VipAddress = loadBalancerIP
+	if loadBalancerIP != "" {
+		if svcConf.internal || (svcConf.preferredIPFamily == corev1.IPv6Protocol) {
+			createOpts.VipAddress = loadBalancerIP
+		}
 	}
 
 	if !lbaas.opts.ProviderRequiresSerialAPICalls {
@@ -1315,9 +1317,6 @@ func (lbaas *LbaasV2) checkService(service *corev1.Service, nodes []*corev1.Node
 			klog.V(3).InfoS("Enforcing internal LB", "annotation", true, "config", false)
 		}
 		svcConf.internal = true
-	} else if svcConf.preferredIPFamily == corev1.IPv6Protocol {
-		// floating IPs are not supported in IPv6 networks
-		svcConf.internal = true
 	} else {
 		svcConf.internal = getBoolFromServiceAnnotation(service, ServiceAnnotationLoadBalancerInternal, lbaas.opts.InternalLB)
 	}
@@ -1711,11 +1710,18 @@ func (lbaas *LbaasV2) ensureOctaviaLoadBalancer(ctx context.Context, clusterName
 		}
 	}
 
-	addr, err := lbaas.ensureFloatingIP(clusterName, service, loadbalancer, svcConf, isLBOwner)
-	if err != nil {
-		return nil, err
+	addr := loadbalancer.VipAddress
+	// IPv6 Load Balancers have no support for Floating IP.
+	if netutils.IsIPv6String(addr) {
+		msg := "Floating IP not supported for IPv6 Service %s. Using IPv6 address instead %s."
+		lbaas.eventRecorder.Eventf(service, corev1.EventTypeWarning, eventLBFloatingIPSkipped, msg, serviceName, addr)
+		klog.Infof(msg, serviceName, addr)
+	} else {
+		addr, err = lbaas.ensureFloatingIP(clusterName, service, loadbalancer, svcConf, isLBOwner)
+		if err != nil {
+			return nil, err
+		}
 	}
-
 	// Add annotation to Service and add LB name to load balancer tags.
 	annotationUpdate := map[string]string{
 		ServiceAnnotationLoadBalancerID:      loadbalancer.ID,