Implement CSI migration logic for volume resize

Author: Cheng Pan

Gopkg.lock

@@ -33,6 +33,8 @@ import (
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
 	storagev1listers "k8s.io/client-go/listers/storage/v1"
+
+	csitranslationlib "k8s.io/csi-translation-lib"
 	"k8s.io/klog"
 )
 
@@ -118,7 +120,13 @@ func (r *csiResizer) Name() string {
 	return r.name
 }
 
+// CanSupport returns whether the PV is supported by resizer
+// Resizer will resize the volume if it is CSI volume or is migration enabled in-tree volume
 func (r *csiResizer) CanSupport(pv *v1.PersistentVolume) bool {
+	if csitranslationlib.IsMigratedCSIDriverByName(r.name) /* && migration enabled*/ {
+		return true
+	}
+
 	source := pv.Spec.CSI
 	if source == nil {
 		klog.V(4).Infof("PV %s is not a CSI volume, skip it", pv.Name)
@@ -131,14 +139,30 @@ func (r *csiResizer) CanSupport(pv *v1.PersistentVolume) bool {
 	return true
 }
 
+// Resize resizes the persistence volume given request size
+// It supports both CSI volume and migrated in-tree volume
 func (r *csiResizer) Resize(pv *v1.PersistentVolume, requestSize resource.Quantity) (resource.Quantity, bool, error) {
 	oldSize := pv.Spec.Capacity[v1.ResourceStorage]
 
-	source := pv.Spec.CSI
-	if source == nil {
-		return oldSize, false, errors.New("not a CSI volume")
+	var volumeID string
+	if pv.Spec.CSI != nil {
+		// handle CSI volume
+		source := pv.Spec.CSI
+		volumeID = source.VolumeHandle
+	} else {
+		if csitranslationlib.IsMigratedCSIDriverByName(r.name) /* && migration enabled*/ {
+			// handle migrated in-tree volume
+			csiPV, err := csitranslationlib.TranslateInTreePVToCSI(pv)
+			if err != nil {
+				return oldSize, false, fmt.Errorf("failed to translate persistenc volume: %v", err)
+			}
+			volumeID = csiPV.Spec.CSI.VolumeHandle
+		} else {
+			// non-migrated in-tree volume
+			return oldSize, false, errors.New("un-supported volume type")
+		}
 	}
-	volumeID := source.VolumeHandle
+
 	if len(volumeID) == 0 {
 		return oldSize, false, errors.New("empty volume handle")
 	}