fix(setting): do not delete the storage class

Delete the old storage class set in reconciling the
`default-longhorn-static-storage-class` setting.
Create the storage with a label if the storage class named as the
value of `default-longhorn-static-storage-class` setting does not
exist.

ref: longhorn/longhorn 9391

Signed-off-by: James Lu <james.lu@suse.com>
(cherry picked from commit f45adc0)

controller/setting_controller.go

@@ -139,7 +139,7 @@ func NewSettingController(
 	var err error
 	if _, err = ds.SettingInformer.AddEventHandlerWithResyncPeriod(cache.ResourceEventHandlerFuncs{
 		AddFunc:    sc.enqueueSetting,
-		UpdateFunc: func(old, cur interface{}) { sc.enqueueUpdateSetting(old, cur) },
+		UpdateFunc: func(old, cur interface{}) { sc.enqueueSetting(cur) },
 		DeleteFunc: sc.enqueueSetting,
 	}, settingControllerResyncPeriod); err != nil {
 		return nil, err
@@ -958,6 +958,18 @@ func (sc *SettingController) syncDefaultLonghornStaticStorageClass() error {
 	}
 
 	defaultStaticStorageClassName := setting.Value
+
+	definition, ok := types.GetSettingDefinition(types.SettingNameDefaultLonghornStaticStorageClass)
+	if !ok {
+		return fmt.Errorf("setting %v is not found", types.SettingNameDefaultLonghornStaticStorageClass)
+	}
+
+	// Only create the default Longhorn static storage class named 'longhorn-static' if it does not exist
+	// And validator will check if the storage class exists when the setting value is not 'longhorn-static'.
+	if defaultStaticStorageClassName != definition.Default {
+		return nil
+	}
+
 	_, err = sc.ds.GetStorageClassRO(defaultStaticStorageClassName)
 	if err != nil && apierrors.IsNotFound(err) {
 		allowVolumeExpansion := true
@@ -1318,31 +1330,6 @@ func (sc *SettingController) enqueueSetting(obj interface{}) {
 	sc.queue.Add(key)
 }
 
-func (sc *SettingController) enqueueUpdateSetting(oldObj, newObj interface{}) {
-	key, err := controller.KeyFunc(newObj)
-	if err != nil {
-		utilruntime.HandleError(fmt.Errorf("failed to get key for object %#v: %v", newObj, err))
-		return
-	}
-
-	oldSetting := oldObj.(*longhorn.Setting)
-	if oldSetting.Name == string(types.SettingNameDefaultLonghornStaticStorageClass) {
-		_, err := sc.ds.GetStorageClassRO(oldSetting.Value)
-		if err == nil {
-			if err := sc.ds.DeleteStorageClass(oldSetting.Value); err != nil {
-				utilruntime.HandleError(fmt.Errorf("failed to delete old %v for object %#v: %v", types.SettingNameDefaultLonghornStaticStorageClass, oldObj, err))
-				return
-			}
-		}
-		if err != nil && !apierrors.IsNotFound(err) {
-			utilruntime.HandleError(fmt.Errorf("failed to get old %v for object %#v: %v", types.SettingNameDefaultLonghornStaticStorageClass, oldObj, err))
-			return
-		}
-	}
-
-	sc.queue.Add(key)
-}
-
 func (sc *SettingController) enqueueSettingForNode(obj interface{}) {
 	if _, ok := obj.(*longhorn.Node); !ok {
 		// Ignore deleted node

datastore/longhorn.go

@@ -402,6 +402,23 @@ func (s *DataStore) ValidateSetting(name, value string) (err error) {
 		if v < 2 || v > 250 {
 			return fmt.Errorf("%s should be between 2 and 250", name)
 		}
+	case types.SettingNameDefaultLonghornStaticStorageClass:
+		definition, ok := types.GetSettingDefinition(types.SettingNameDefaultLonghornStaticStorageClass)
+		if !ok {
+			return fmt.Errorf("setting %v is not found", types.SettingNameDefaultLonghornStaticStorageClass)
+		}
+
+		if value == definition.Default {
+			return nil
+		}
+
+		_, err := s.GetStorageClassRO(value)
+		if err != nil {
+			if apierrors.IsNotFound(err) {
+				return errors.Wrapf(err, "cannot use a storage class %v that does not exist to set the setting %v", value, types.SettingNameDefaultLonghornStaticStorageClass)
+			}
+			return errors.Wrapf(err, "failed to get the storage class %v for setting %v", value, types.SettingNameDefaultLonghornStaticStorageClass)
+		}
 	}
 	return nil
 }