Merge pull request #103470 from nilo19/bug/cherry-pick-679

fix: return empty VMAS name if using standalone VM

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

@@ -1034,6 +1034,11 @@ func (as *availabilitySet) EnsureBackendPoolDeleted(service *v1.Service, backend
 }
 
 func getAvailabilitySetNameByID(asID string) (string, error) {
+	// for standalone VM
+	if asID == "" {
+		return "", nil
+	}
+
 	matches := vmasIDRE.FindStringSubmatch(asID)
 	if len(matches) != 2 {
 		return "", fmt.Errorf("getAvailabilitySetNameByID: failed to parse the VMAS ID %s", asID)

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

@@ -1747,3 +1747,25 @@ func TestStandardGetNodeNameByIPConfigurationID(t *testing.T) {
 	assert.Equal(t, "k8s-agentpool1-00000000-0", nodeName)
 	assert.Equal(t, "agentpool1-availabilityset-00000000", asName)
 }
+
+func TestGetAvailabilitySetNameByID(t *testing.T) {
+	t.Run("getAvailabilitySetNameByID should return empty string if the given ID is empty", func(t *testing.T) {
+		vmasName, err := getAvailabilitySetNameByID("")
+		assert.Nil(t, err)
+		assert.Empty(t, vmasName)
+	})
+
+	t.Run("getAvailabilitySetNameByID should report an error if the format of the given ID is wrong", func(t *testing.T) {
+		asID := "illegal-id"
+		vmasName, err := getAvailabilitySetNameByID(asID)
+		assert.Equal(t, fmt.Errorf("getAvailabilitySetNameByID: failed to parse the VMAS ID illegal-id"), err)
+		assert.Empty(t, vmasName)
+	})
+
+	t.Run("getAvailabilitySetNameByID should extract the VMAS name from the given ID", func(t *testing.T) {
+		asID := "/subscriptions/sub/resourceGroups/rg/providers/Microsoft.Compute/availabilitySets/as"
+		vmasName, err := getAvailabilitySetNameByID(asID)
+		assert.Nil(t, err)
+		assert.Equal(t, "as", vmasName)
+	})
+}