Skip privatedns zones on Azure Stack

Azure Stack Hub does not support private dns zones, so skip them.

Author: patrickdillon

azure/scope/cluster.go

@@ -558,7 +558,7 @@ func (s *ClusterScope) VNetSpec() azure.ASOResourceSpecGetter[*asonetworkv1api20
 
 // PrivateDNSSpec returns the private dns zone spec.
 func (s *ClusterScope) PrivateDNSSpec() (zoneSpec azure.ResourceSpecGetter, linkSpec, recordSpec []azure.ResourceSpecGetter) {
-	if s.IsAPIServerPrivate() {
+	if s.IsAPIServerPrivate() && !s.IsHybridEnvironment() {
 		resourceGroup := s.ResourceGroup()
 		if s.AzureCluster.Spec.NetworkSpec.PrivateDNSZoneResourceGroup != "" {
 			resourceGroup = s.AzureCluster.Spec.NetworkSpec.PrivateDNSZoneResourceGroup
@@ -1234,3 +1234,8 @@ func (s *ClusterScope) getLastAppliedSecurityRules(nsgName string) map[string]in
 	}
 	return lastAppliedSecurityRules
 }
+
+// IsHybridEnvironment returns true if the cluster is running on Azure Stack.
+func (s *ClusterScope) IsHybridEnvironment() bool {
+	return strings.EqualFold(s.Environment.Name, azure.StackCloudName)
+}