Skip ensuring VMSS in pool for nodes which should be excluded from lb

Such nodes should not be added to backend pools. This has particular impact
for nodes which are not master nodes (such as nodes running an etcd cluster)
and are incorrectly added to the pool prior to this change.

staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go

@@ -954,6 +954,12 @@ func (ss *scaleSet) ensureVMSSInPool(service *v1.Service, nodes []*v1.Node, back
 			if ss.excludeMasterNodesFromStandardLB() && isMasterNode(node) {
 				continue
 			}
+
+			if ss.ShouldNodeExcludedFromLoadBalancer(node) {
+				klog.V(4).Infof("Excluding unmanaged/external-resource-group node %q", node.Name)
+				continue
+			}
+
 			// in this scenario the vmSetName is an empty string and the name of vmss should be obtained from the provider IDs of nodes
 			resourceGroupName, vmssName, err := getVmssAndResourceGroupNameByVMProviderID(node.Spec.ProviderID)
 			if err != nil {