diff --git a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go
index 4143bda3d65..8504aada304 100644
--- a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go
+++ b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss.go
@@ -740,7 +740,7 @@ func (ss *scaleSet) getAgentPoolScaleSets(nodes []*v1.Node) (*[]string, error) {
 // (depending vmType configured) for service load balancer. If the service has
 // no loadbalancer mode annotation returns the primary VMSet. If service annotation
 // for loadbalancer exists then return the eligible VMSet.
-func (ss *scaleSet) GetVMSetNames(service *v1.Service, nodes []*v1.Node) (vmSetNames *[]string, err error) {
+func (ss *scaleSet) GetVMSetNames(service *v1.Service, nodes []*v1.Node) (*[]string, error) {
 	hasMode, isAuto, serviceVMSetNames := getServiceLoadBalancerMode(service)
 	useSingleSLB := ss.useStandardLoadBalancer() && !ss.EnableMultipleStandardLoadBalancers
 	if !hasMode || useSingleSLB {
@@ -764,7 +764,7 @@ func (ss *scaleSet) GetVMSetNames(service *v1.Service, nodes []*v1.Node) (vmSetN
 	sort.Strings(*scaleSetNames)
 
 	if !isAuto {
-		if serviceVMSetNames == nil || len(serviceVMSetNames) == 0 {
+		if len(serviceVMSetNames) == 0 {
 			return nil, fmt.Errorf("service annotation for LoadBalancerMode is empty, it should have __auto__ or availability sets value")
 		}
 		// validate scale set exists
@@ -782,10 +782,10 @@ func (ss *scaleSet) GetVMSetNames(service *v1.Service, nodes []*v1.Node) (vmSetN
 				return nil, fmt.Errorf("scale set (%s) - not found", serviceVMSetNames[sasx])
 			}
 		}
-		vmSetNames = &serviceVMSetNames
+		scaleSetNames = &serviceVMSetNames
 	}
 
-	return vmSetNames, nil
+	return scaleSetNames, nil
 }
 
 // extractResourceGroupByVMSSNicID extracts the resource group name by vmss nicID.
diff --git a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss_test.go b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss_test.go
index 27d5c4d2a0c..3d5a00d7e79 100644
--- a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss_test.go
+++ b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_vmss_test.go
@@ -1436,7 +1436,7 @@ func TestGetVMSetNames(t *testing.T) {
 			expectedVMSetNames: &[]string{"vmss"},
 		},
 		{
-			description: "GetVMSetNames should return nil if the service has auto mode annotation",
+			description: "GetVMSetNames should return all scale sets if the service has auto mode annotation",
 			service: &v1.Service{
 				ObjectMeta: metav1.ObjectMeta{Annotations: map[string]string{ServiceAnnotationLoadBalancerMode: ServiceAnnotationLoadBalancerAutoModeValue}},
 			},
@@ -1447,6 +1447,7 @@ func TestGetVMSetNames(t *testing.T) {
 					},
 				},
 			},
+			expectedVMSetNames: &[]string{"vmss"},
 		},
 		{
 			description: "GetVMSetNames should report the error if there's no such vmss",
@@ -1516,7 +1517,7 @@ func TestGetVMSetNames(t *testing.T) {
 
 		vmSetNames, err := ss.GetVMSetNames(test.service, test.nodes)
 		assert.Equal(t, test.expectedErr, err, test.description+", but an error occurs")
-		assert.Equal(t, test.expectedVMSetNames, vmSetNames)
+		assert.Equal(t, test.expectedVMSetNames, vmSetNames, test.description)
 	}
 }