inherit k8s default volumeSnapshotClass

Signed-off-by: hu-keyu <[email protected]>

Author: hu-keyu

changelogs/unreleased/8719-hu-keyu

@@ -0,0 +1 @@
+Inherit k8s default volumeSnapshotClass.

pkg/apis/velero/v1/labels_annotations.go

@@ -127,6 +127,9 @@ const (
 	VolumeSnapshotClassDriverBackupAnnotationPrefix = "velero.io/csi-volumesnapshot-class"
 	VolumeSnapshotClassDriverPVCAnnotation          = "velero.io/csi-volumesnapshot-class"
 
+	// https://kubernetes.io/zh-cn/docs/concepts/storage/volume-snapshot-classes/
+	VolumeSnapshotClassKubernetesAnnotation = "snapshot.storage.kubernetes.io/is-default-class"
+
 	// There is no release w/ these constants exported. Using the strings for now.
 	// CSI Annotation volumesnapshotclass
 	// https://github.com/kubernetes-csi/external-snapshotter/blob/master/pkg/utils/util.go#L59-L60

pkg/util/csi/volume_snapshot.go

@@ -432,13 +432,23 @@ func GetVolumeSnapshotClassForStorageClass(
 			}
 		}
 	}
+	// not found by label, pick by annotation
+	for _, sc := range snapshotClasses.Items {
+		_, hasDefaultAnnotation := sc.Annotations[velerov1api.VolumeSnapshotClassKubernetesAnnotation]
+		if sc.Driver == provisioner {
+			vsClass = sc
+			if hasDefaultAnnotation {
+				return &sc, nil
+			}
+		}
+	}
 	// If there's only one volumesnapshotclass for the driver, return it.
 	if n == 1 {
 		return &vsClass, nil
 	}
 	return nil, fmt.Errorf(
-		"failed to get VolumeSnapshotClass for provisioner %s, ensure that the desired VolumeSnapshot class has the %s label",
-		provisioner, velerov1api.VolumeSnapshotClassSelectorLabel)
+		"failed to get VolumeSnapshotClass for provisioner %s, ensure that the desired VolumeSnapshot class has the %s label or %s annotation",
+		provisioner, velerov1api.VolumeSnapshotClassSelectorLabel, velerov1api.VolumeSnapshotClassKubernetesAnnotation)
 }
 
 // IsVolumeSnapshotClassHasListerSecret returns whether a volumesnapshotclass has a snapshotlister secret