use default backend pool name in capz controller if empty

Ref issue kubernetes-sigs#3252

Signed-off-by: Ashutosh Kumar <[email protected]>

azure/scope/cluster.go

@@ -230,6 +230,40 @@ func (s *ClusterScope) PublicIPSpecs() []azure.ResourceSpecGetter {
 	return publicIPSpecs
 }
 
+// SetAPIServerLBBackendPoolName sets the name of the backend pool for apiserver LB.
+func (s *ClusterScope) SetAPIServerLBBackendPoolName() {
+	// Ref issue #3253
+	if s.APIServerLB().BackendPool.Name == "" {
+		s.APIServerLB().BackendPool.Name = s.APIServerLBPoolName(s.APIServerLB().Name)
+	}
+}
+
+// SetNodeOutboundLBBackendPoolName sets the name of the backend pool for node outbound LB.
+func (s *ClusterScope) SetNodeOutboundLBBackendPoolName() {
+	// Ref issue #3253
+	if s.NodeOutboundLB() != nil && s.NodeOutboundLB().BackendPool.Name == "" {
+		s.NodeOutboundLB().BackendPool.Name = s.OutboundPoolName(s.NodeOutboundLB().Name)
+	}
+}
+
+// SetControlPlaneOutboundLBBackendPoolName sets the name of the backend pool for control plane outbound LB.
+func (s *ClusterScope) SetControlPlaneOutboundLBBackendPoolName() {
+	// Ref issue #3253
+	if s.ControlPlaneOutboundLB() != nil && s.ControlPlaneOutboundLB().BackendPool.Name == "" {
+		s.ControlPlaneOutboundLB().BackendPool.Name = s.OutboundPoolName(azure.GenerateControlPlaneOutboundLBName(s.ClusterName()))
+	}
+}
+
+// SetLBBackendPoolName sets the backend pool name for different LBs.
+// Note: This logic exists only for the purpose of backwards compatibility for old clusters for which
+// backend pool name was not required and may be removed in the future.
+// Please refer to issue #3252 for more details (@sonasingh46).
+func (s *ClusterScope) SetLBBackendPoolName() {
+	s.SetAPIServerLBBackendPoolName()
+	s.SetNodeOutboundLBBackendPoolName()
+	s.SetControlPlaneOutboundLBBackendPoolName()
+}
+
 // LBSpecs returns the load balancer specs.
 func (s *ClusterScope) LBSpecs() []azure.ResourceSpecGetter {
 	specs := []azure.ResourceSpecGetter{

controllers/azurecluster_reconciler.go

@@ -85,6 +85,7 @@ func (s *azureClusterService) Reconcile(ctx context.Context) error {
 		return errors.Wrap(err, "failed to get availability zones")
 	}
 
+	s.scope.SetLBBackendPoolName()
 	s.scope.SetDNSName()
 	s.scope.SetControlPlaneSecurityRules()