Merge pull request #826 from RaunakShah/group-create

Create Group Snapshot functionality for volume group snapshots

client/apis/volumegroupsnapshot/v1alpha1/types.go

@@ -326,7 +326,7 @@ type VolumeGroupSnapshotContentStatus struct {
 	// for this group snapshot.
 	// The maximum number of allowed snapshots in the group is 100.
 	// +optional
-	VolumeSnapshotContentRefList []core_v1.ObjectReference `json:"volumeSnapshotRefList,omitempty" protobuf:"bytes,5,opt,name=volumeSnapshotRefList"`
+	VolumeSnapshotContentRefList []core_v1.ObjectReference `json:"volumeSnapshotContentRefList,omitempty" protobuf:"bytes,5,opt,name=volumeSnapshotContentRefList"`
 }
 
 // VolumeGroupSnapshotContentSource represents the CSI source of a group snapshot.

cmd/csi-snapshotter/main.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/group_snapshotter"
 	"net/http"
 	"os"
 	"os/signal"
@@ -79,12 +80,16 @@ var (
 	kubeAPIQPS   = flag.Float64("kube-api-qps", 5, "QPS to use while communicating with the kubernetes apiserver. Defaults to 5.0.")
 	kubeAPIBurst = flag.Int("kube-api-burst", 10, "Burst to use while communicating with the kubernetes apiserver. Defaults to 10.")
 
-	metricsAddress       = flag.String("metrics-address", "", "(deprecated) The TCP network address where the prometheus metrics endpoint will listen (example: `:8080`). The default is empty string, which means metrics endpoint is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
-	httpEndpoint         = flag.String("http-endpoint", "", "The TCP network address where the HTTP server for diagnostics, including metrics and leader election health check, will listen (example: `:8080`). The default is empty string, which means the server is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
-	metricsPath          = flag.String("metrics-path", "/metrics", "The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.")
-	retryIntervalStart   = flag.Duration("retry-interval-start", time.Second, "Initial retry interval of failed volume snapshot creation or deletion. It doubles with each failure, up to retry-interval-max. Default is 1 second.")
-	retryIntervalMax     = flag.Duration("retry-interval-max", 5*time.Minute, "Maximum retry interval of failed volume snapshot creation or deletion. Default is 5 minutes.")
-	enableNodeDeployment = flag.Bool("node-deployment", false, "Enables deploying the sidecar controller together with a CSI driver on nodes to manage snapshots for node-local volumes.")
+	metricsAddress             = flag.String("metrics-address", "", "(deprecated) The TCP network address where the prometheus metrics endpoint will listen (example: `:8080`). The default is empty string, which means metrics endpoint is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
+	httpEndpoint               = flag.String("http-endpoint", "", "The TCP network address where the HTTP server for diagnostics, including metrics and leader election health check, will listen (example: `:8080`). The default is empty string, which means the server is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
+	metricsPath                = flag.String("metrics-path", "/metrics", "The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.")
+	retryIntervalStart         = flag.Duration("retry-interval-start", time.Second, "Initial retry interval of failed volume snapshot creation or deletion. It doubles with each failure, up to retry-interval-max. Default is 1 second.")
+	retryIntervalMax           = flag.Duration("retry-interval-max", 5*time.Minute, "Maximum retry interval of failed volume snapshot creation or deletion. Default is 5 minutes.")
+	enableNodeDeployment       = flag.Bool("node-deployment", false, "Enables deploying the sidecar controller together with a CSI driver on nodes to manage snapshots for node-local volumes.")
+	enableVolumeGroupSnapshots = flag.Bool("enable-volume-group-snapshots", false, "Enables the volume group snapshot feature, allowing the user to create snapshots of groups of volumes.")
+
+	groupSnapshotNamePrefix     = flag.String("groupsnapshot-name-prefix", "groupsnapshot", "Prefix to apply to the name of a created group snapshot")
+	groupSnapshotNameUUIDLength = flag.Int("groupsnapshot-name-uuid-length", -1, "Length in characters for the generated uuid of a created group snapshot. Defaults behavior is to NOT truncate.")
 )
 
 var (
@@ -222,6 +227,15 @@ func main() {
 	klog.V(2).Infof("Start NewCSISnapshotSideCarController with snapshotter [%s] kubeconfig [%s] csiTimeout [%+v] csiAddress [%s] resyncPeriod [%+v] snapshotNamePrefix [%s] snapshotNameUUIDLength [%d]", driverName, *kubeconfig, *csiTimeout, *csiAddress, *resyncPeriod, *snapshotNamePrefix, snapshotNameUUIDLength)
 
 	snapShotter := snapshotter.NewSnapshotter(csiConn)
+	var groupSnapshotter group_snapshotter.GroupSnapshotter
+	if *enableVolumeGroupSnapshots {
+		groupSnapshotter = group_snapshotter.NewGroupSnapshotter(csiConn)
+		if len(*groupSnapshotNamePrefix) == 0 {
+			klog.Error("group snapshot name prefix cannot be of length 0")
+			os.Exit(1)
+		}
+	}
+
 	ctrl := controller.NewCSISnapshotSideCarController(
 		snapClient,
 		kubeClient,
@@ -229,12 +243,19 @@ func main() {
 		snapshotContentfactory.Snapshot().V1().VolumeSnapshotContents(),
 		factory.Snapshot().V1().VolumeSnapshotClasses(),
 		snapShotter,
+		groupSnapshotter,
 		*csiTimeout,
 		*resyncPeriod,
 		*snapshotNamePrefix,
 		*snapshotNameUUIDLength,
+		*groupSnapshotNamePrefix,
+		*groupSnapshotNameUUIDLength,
 		*extraCreateMetadata,
 		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
+		*enableVolumeGroupSnapshots,
+		snapshotContentfactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotContents(),
+		snapshotContentfactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotClasses(),
+		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
 	)
 
 	run := func(context.Context) {

cmd/snapshot-controller/main.go

@@ -72,6 +72,7 @@ var (
 	retryIntervalMax              = flag.Duration("retry-interval-max", 5*time.Minute, "Maximum retry interval of failed volume snapshot creation or deletion. Default is 5 minutes.")
 	enableDistributedSnapshotting = flag.Bool("enable-distributed-snapshotting", false, "Enables each node to handle snapshotting for the local volumes created on that node")
 	preventVolumeModeConversion   = flag.Bool("prevent-volume-mode-conversion", false, "Prevents an unauthorised user from modifying the volume mode when creating a PVC from an existing VolumeSnapshot.")
+	enableVolumeGroupSnapshots    = flag.Bool("enable-volume-group-snapshots", false, "Enables the volume group snapshot feature, allowing the user to create snapshots of groups of volumes.")
 
 	retryCRDIntervalMax = flag.Duration("retry-crd-interval-max", 5*time.Second, "Maximum retry interval to wait for CRDs to appear. The default is 5 seconds.")
 )
@@ -193,14 +194,20 @@ func main() {
 		factory.Snapshot().V1().VolumeSnapshots(),
 		factory.Snapshot().V1().VolumeSnapshotContents(),
 		factory.Snapshot().V1().VolumeSnapshotClasses(),
+		factory.Groupsnapshot().V1alpha1().VolumeGroupSnapshots(),
+		factory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotContents(),
+		factory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotClasses(),
 		coreFactory.Core().V1().PersistentVolumeClaims(),
 		nodeInformer,
 		metricsManager,
 		*resyncPeriod,
 		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
 		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
+		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
+		workqueue.NewItemExponentialFailureRateLimiter(*retryIntervalStart, *retryIntervalMax),
 		*enableDistributedSnapshotting,
 		*preventVolumeModeConversion,
+		*enableVolumeGroupSnapshots,
 	)
 
 	if err := ensureCustomResourceDefinitionsExist(snapClient); err != nil {

go.mod

@@ -3,7 +3,7 @@ module github.com/kubernetes-csi/external-snapshotter/v6
 go 1.20
 
 require (
-	github.com/container-storage-interface/spec v1.7.0
+	github.com/container-storage-interface/spec v1.8.0
 	github.com/evanphx/json-patch v4.12.0+incompatible
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/golang/mock v1.6.0

go.sum

@@ -60,8 +60,8 @@ github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGX
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/container-storage-interface/spec v1.3.0/go.mod h1:6URME8mwIBbpVyZV93Ce5St17xBiQJQY67NDsuohiy4=
-github.com/container-storage-interface/spec v1.7.0 h1:gW8eyFQUZWWrMWa8p1seJ28gwDoN5CVJ4uAbQ+Hdycw=
-github.com/container-storage-interface/spec v1.7.0/go.mod h1:JYuzLqr9VVNoDJl44xp/8fmCOvWPDKzuGTwCoklhuqk=
+github.com/container-storage-interface/spec v1.8.0 h1:D0vhF3PLIZwlwZEf2eNbpujGCNwspwTYf2idJRJx4xI=
+github.com/container-storage-interface/spec v1.8.0/go.mod h1:ROLik+GhPslwwWRNFF1KasPzroNARibH2rfz1rkg4H0=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

pkg/common-controller/framework_test.go

@@ -842,12 +842,18 @@ func newTestController(kubeClient kubernetes.Interface, clientset clientset.Inte
 		informerFactory.Snapshot().V1().VolumeSnapshots(),
 		informerFactory.Snapshot().V1().VolumeSnapshotContents(),
 		informerFactory.Snapshot().V1().VolumeSnapshotClasses(),
+		informerFactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshots(),
+		informerFactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotContents(),
+		informerFactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotClasses(),
 		coreFactory.Core().V1().PersistentVolumeClaims(),
 		nil,
 		metricsManager,
 		60*time.Second,
 		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
 		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
+		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
+		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
+		false,
 		false,
 		false,
 	)

pkg/common-controller/groupsnapshot_controller_helper.go

@@ -0,0 +1,937 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package common_controller
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	apierrs "k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/client-go/kubernetes/scheme"
+	ref "k8s.io/client-go/tools/reference"
+	klog "k8s.io/klog/v2"
+
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
+)
+
+func (ctrl *csiSnapshotCommonController) storeGroupSnapshotUpdate(groupsnapshot interface{}) (bool, error) {
+	return utils.StoreObjectUpdate(ctrl.groupSnapshotStore, groupsnapshot, "groupsnapshot")
+}
+
+func (ctrl *csiSnapshotCommonController) storeGroupSnapshotContentUpdate(groupsnapshotcontent interface{}) (bool, error) {
+	return utils.StoreObjectUpdate(ctrl.groupSnapshotContentStore, groupsnapshotcontent, "groupsnapshotcontent")
+}
+
+// getGroupSnapshotClass is a helper function to get group snapshot class from the group snapshot class name.
+func (ctrl *csiSnapshotCommonController) getGroupSnapshotClass(className string) (*crdv1alpha1.VolumeGroupSnapshotClass, error) {
+	klog.V(5).Infof("getGroupSnapshotClass: VolumeGroupSnapshotClassName [%s]", className)
+
+	groupSnapshotClass, err := ctrl.groupSnapshotClassLister.Get(className)
+	if err != nil {
+		klog.Errorf("failed to retrieve group snapshot class %s from the informer: %q", className, err)
+		return nil, err
+	}
+
+	return groupSnapshotClass, nil
+}
+
+// updateGroupSnapshotErrorStatusWithEvent saves new groupsnapshot.Status to API
+// server and emits given event on the group snapshot. It saves the status and
+// emits the event only when the status has actually changed from the version
+// saved in API server.
+//
+// Parameters:
+//
+//   - groupSnapshot - group snapshot to update
+//   - setReadyToFalse bool - indicates whether to set the group snapshot's
+//     ReadyToUse status to false.
+//     if true, ReadyToUse will be set to false;
+//     otherwise, ReadyToUse will not be changed.
+//   - eventtype, reason, message - event to send, see EventRecorder.Event()
+func (ctrl *csiSnapshotCommonController) updateGroupSnapshotErrorStatusWithEvent(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot, setReadyToFalse bool, eventtype, reason, message string) error {
+	klog.V(5).Infof("updateGroupSnapshotErrorStatusWithEvent[%s]", utils.GroupSnapshotKey(groupSnapshot))
+
+	if groupSnapshot.Status != nil && groupSnapshot.Status.Error != nil && *groupSnapshot.Status.Error.Message == message {
+		klog.V(4).Infof("updateGroupSnapshotErrorStatusWithEvent[%s]: the same error %v is already set", groupSnapshot.Name, groupSnapshot.Status.Error)
+		return nil
+	}
+	groupSnapshotClone := groupSnapshot.DeepCopy()
+	if groupSnapshotClone.Status == nil {
+		groupSnapshotClone.Status = &crdv1alpha1.VolumeGroupSnapshotStatus{}
+	}
+	statusError := &crdv1.VolumeSnapshotError{
+		Time: &metav1.Time{
+			Time: time.Now(),
+		},
+		Message: &message,
+	}
+	groupSnapshotClone.Status.Error = statusError
+	// Only update ReadyToUse in VolumeGroupSnapshot's Status to false if setReadyToFalse is true.
+	if setReadyToFalse {
+		ready := false
+		groupSnapshotClone.Status.ReadyToUse = &ready
+	}
+	newSnapshot, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshots(groupSnapshotClone.Namespace).UpdateStatus(context.TODO(), groupSnapshotClone, metav1.UpdateOptions{})
+
+	// Emit the event even if the status update fails so that user can see the error
+	ctrl.eventRecorder.Event(newSnapshot, eventtype, reason, message)
+
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshot[%s] error status failed %v", utils.GroupSnapshotKey(groupSnapshot), err)
+		return err
+	}
+
+	_, err = ctrl.storeGroupSnapshotUpdate(newSnapshot)
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshot[%s] error status: cannot update internal cache %v", utils.GroupSnapshotKey(groupSnapshot), err)
+		return err
+	}
+
+	return nil
+}
+
+// SetDefaultGroupSnapshotClass is a helper function to figure out the default
+// group snapshot class.
+// For pre-provisioned case, it's an no-op.
+// For dynamic provisioning, it gets the default GroupSnapshotClasses in the
+// system if there is any (could be multiple), and finds the one with the same
+// CSI Driver as a PV from which a group snapshot will be taken.
+func (ctrl *csiSnapshotCommonController) SetDefaultGroupSnapshotClass(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshotClass, *crdv1alpha1.VolumeGroupSnapshot, error) {
+	klog.V(5).Infof("SetDefaultGroupSnapshotClass for group snapshot [%s]", groupSnapshot.Name)
+
+	if groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName != nil {
+		// don't return error for pre-provisioned group snapshots
+		klog.V(5).Infof("Don't need to find GroupSnapshotClass for pre-provisioned group snapshot [%s]", groupSnapshot.Name)
+		return nil, groupSnapshot, nil
+	}
+
+	// Find default group snapshot class if available
+	list, err := ctrl.groupSnapshotClassLister.List(labels.Everything())
+	if err != nil {
+		return nil, groupSnapshot, err
+	}
+
+	pvDriver, err := ctrl.pvDriverFromGroupSnapshot(groupSnapshot)
+	if err != nil {
+		klog.Errorf("failed to get pv csi driver from group snapshot %s/%s: %q", groupSnapshot.Namespace, groupSnapshot.Name, err)
+		return nil, groupSnapshot, err
+	}
+
+	defaultClasses := []*crdv1alpha1.VolumeGroupSnapshotClass{}
+	for _, groupSnapshotClass := range list {
+		if utils.IsDefaultAnnotation(groupSnapshotClass.ObjectMeta) && pvDriver == groupSnapshotClass.Driver {
+			defaultClasses = append(defaultClasses, groupSnapshotClass)
+			klog.V(5).Infof("get defaultGroupClass added: %s, driver: %s", groupSnapshotClass.Name, pvDriver)
+		}
+	}
+	if len(defaultClasses) == 0 {
+		return nil, groupSnapshot, fmt.Errorf("cannot find default group snapshot class")
+	}
+	if len(defaultClasses) > 1 {
+		klog.V(4).Infof("get DefaultGroupSnapshotClass %d defaults found", len(defaultClasses))
+		return nil, groupSnapshot, fmt.Errorf("%d default snapshot classes were found", len(defaultClasses))
+	}
+	klog.V(5).Infof("setDefaultGroupSnapshotClass [%s]: default VolumeGroupSnapshotClassName [%s]", groupSnapshot.Name, defaultClasses[0].Name)
+	groupSnapshotClone := groupSnapshot.DeepCopy()
+	groupSnapshotClone.Spec.VolumeGroupSnapshotClassName = &(defaultClasses[0].Name)
+	newGroupSnapshot, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshots(groupSnapshotClone.Namespace).Update(context.TODO(), groupSnapshotClone, metav1.UpdateOptions{})
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshot[%s] default group snapshot class failed %v", utils.GroupSnapshotKey(groupSnapshot), err)
+	}
+	_, updateErr := ctrl.storeGroupSnapshotUpdate(newGroupSnapshot)
+	if updateErr != nil {
+		// We will get a "group snapshot update" event soon, this is not a big error
+		klog.V(4).Infof("setDefaultSnapshotClass [%s]: cannot update internal cache: %v", utils.GroupSnapshotKey(groupSnapshot), updateErr)
+	}
+
+	return defaultClasses[0], newGroupSnapshot, nil
+}
+
+// pvDriverFromGroupSnapshot is a helper function to get the CSI driver name from the targeted persistent volume.
+// It looks up every PVC from which the group snapshot is specified to be created from, and looks for the PVC's
+// corresponding PV. Bi-directional binding will be verified between PVC and PV before the PV's CSI driver is returned.
+// For an non-CSI volume, it returns an error immediately as it's not supported.
+func (ctrl *csiSnapshotCommonController) pvDriverFromGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (string, error) {
+	pvs, err := ctrl.getVolumesFromVolumeGroupSnapshot(groupSnapshot)
+	if err != nil {
+		return "", err
+	}
+	// Take any volume to get the driver
+	if pvs[0].Spec.PersistentVolumeSource.CSI == nil {
+		return "", fmt.Errorf("snapshotting non-CSI volumes is not supported, group snapshot:%s/%s", groupSnapshot.Namespace, groupSnapshot.Name)
+	}
+	return pvs[0].Spec.PersistentVolumeSource.CSI.Driver, nil
+}
+
+// getVolumesFromVolumeGroupSnapshot returns the list of PersistentVolume from a VolumeGroupSnapshot.
+func (ctrl *csiSnapshotCommonController) getVolumesFromVolumeGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) ([]*v1.PersistentVolume, error) {
+	var pvReturnList []*v1.PersistentVolume
+	pvcs, err := ctrl.getClaimsFromVolumeGroupSnapshot(groupSnapshot)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, pvc := range pvcs {
+		if pvc.Status.Phase != v1.ClaimBound {
+			return nil, fmt.Errorf("the PVC %s is not yet bound to a PV, will not attempt to take a group snapshot", pvc.Name)
+		}
+		pvName := pvc.Spec.VolumeName
+		pv, err := ctrl.client.CoreV1().PersistentVolumes().Get(context.TODO(), pvName, metav1.GetOptions{})
+		if err != nil {
+			return nil, fmt.Errorf("failed to retrieve PV %s from the API server: %q", pvName, err)
+		}
+
+		// Verify binding between PV/PVC is still valid
+		bound := ctrl.isVolumeBoundToClaim(pv, &pvc)
+		if bound == false {
+			klog.Warningf("binding between PV %s and PVC %s is broken", pvName, pvc.Name)
+			return nil, fmt.Errorf("claim in dataSource not bound or invalid")
+		}
+		pvReturnList = append(pvReturnList, pv)
+		klog.V(5).Infof("getVolumeFromVolumeGroupSnapshot: group snapshot [%s] PV name [%s]", groupSnapshot.Name, pvName)
+	}
+
+	return pvReturnList, nil
+}
+
+// getClaimsFromVolumeGroupSnapshot is a helper function to get a list of PVCs from VolumeGroupSnapshot.
+func (ctrl *csiSnapshotCommonController) getClaimsFromVolumeGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) ([]v1.PersistentVolumeClaim, error) {
+	labelSelector := groupSnapshot.Spec.Source.Selector
+
+	// Get PVC that has group snapshot label applied.
+	pvcList, err := ctrl.client.CoreV1().PersistentVolumeClaims(groupSnapshot.Namespace).List(context.TODO(), metav1.ListOptions{LabelSelector: labels.Set(labelSelector.MatchLabels).String()})
+	if err != nil {
+		return nil, fmt.Errorf("failed to list PVCs with label selector %s: %q", labelSelector.String(), err)
+	}
+	if len(pvcList.Items) == 0 {
+		return nil, fmt.Errorf("label selector %s for group snapshot not applied to any PVC", labelSelector.String())
+	}
+	return pvcList.Items, nil
+}
+
+// updateGroupSnapshot runs in worker thread and handles "groupsnapshot added",
+// "groupsnapshot updated" and "periodic sync" events.
+func (ctrl *csiSnapshotCommonController) updateGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) error {
+	// Store the new group snapshot version in the cache and do not process it
+	// if this is an old version.
+	klog.V(5).Infof("updateGroupSnapshot %q", utils.GroupSnapshotKey(groupSnapshot))
+	newGroupSnapshot, err := ctrl.storeGroupSnapshotUpdate(groupSnapshot)
+	if err != nil {
+		klog.Errorf("%v", err)
+	}
+	if !newGroupSnapshot {
+		return nil
+	}
+
+	err = ctrl.syncGroupSnapshot(groupSnapshot)
+	if err != nil {
+		if errors.IsConflict(err) {
+			// Version conflict error happens quite often and the controller
+			// recovers from it easily.
+			klog.V(3).Infof("could not sync group snapshot %q: %+v", utils.GroupSnapshotKey(groupSnapshot), err)
+		} else {
+			klog.Errorf("could not sync group snapshot %q: %+v", utils.GroupSnapshotKey(groupSnapshot), err)
+		}
+		return err
+	}
+	return nil
+}
+
+// deleteGroupSnapshot runs in worker thread and handles "groupsnapshot deleted" event.
+func (ctrl *csiSnapshotCommonController) deleteGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) {
+	_ = ctrl.snapshotStore.Delete(groupSnapshot)
+	klog.V(4).Infof("group snapshot %q deleted", utils.GroupSnapshotKey(groupSnapshot))
+
+	groupSnapshotContentName := ""
+	if groupSnapshot.Status != nil && groupSnapshot.Status.BoundVolumeGroupSnapshotContentName != nil {
+		groupSnapshotContentName = *groupSnapshot.Status.BoundVolumeGroupSnapshotContentName
+	}
+	if groupSnapshotContentName == "" {
+		klog.V(5).Infof("deleteGroupSnapshot[%q]: group snapshot content not bound", utils.GroupSnapshotKey(groupSnapshot))
+		return
+	}
+
+	// sync the group snapshot content when its group snapshot is deleted.  Explicitly sync'ing
+	// the group snapshot content here in response to group snapshot deletion prevents the group
+	// snapshot content from waiting until the next sync period for its release.
+	klog.V(5).Infof("deleteGroupSnapshot[%q]: scheduling sync of group snapshot content %s", utils.GroupSnapshotKey(groupSnapshot), groupSnapshotContentName)
+	ctrl.groupSnapshotContentQueue.Add(groupSnapshotContentName)
+}
+
+// syncGroupSnapshot is the main controller method to decide what to do with a
+// group snapshot. It's invoked by appropriate cache.Controller callbacks when
+// a group snapshot is created, updated or periodically synced. We do not
+// differentiate between these events.
+// For easier readability, it is split into syncUnreadyGroupSnapshot and syncReadyGroupSnapshot
+func (ctrl *csiSnapshotCommonController) syncGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) error {
+	klog.V(5).Infof("synchronizing VolumeGroupSnapshot[%s]", utils.GroupSnapshotKey(groupSnapshot))
+
+	klog.V(5).Infof("syncGroupSnapshot [%s]: check if we should remove finalizer on group snapshot PVC source and remove it if we can", utils.GroupSnapshotKey(groupSnapshot))
+
+	/*
+		TODO:
+		- Check and remove finalizer if needed.
+		- Check and set invalid group snapshot label, if needed.
+		- Process if deletion timestamp is set.
+		- Check and add group snapshot finalizers.
+	*/
+
+	// Need to build or update groupSnapshot.Status in following cases:
+	// 1) groupSnapshot.Status is nil
+	// 2) groupSnapshot.Status.ReadyToUse is false
+	// 3) groupSnapshot.Status.IsBoundVolumeGroupSnapshotContentNameSet is not set
+	// 4) groupSnapshot.Status.IsVolumeSnapshotRefListSet is not set
+	if !utils.IsGroupSnapshotReady(groupSnapshot) || !utils.IsBoundVolumeGroupSnapshotContentNameSet(groupSnapshot) || !utils.IsVolumeSnapshotRefListSet(groupSnapshot) {
+		return ctrl.syncUnreadyGroupSnapshot(groupSnapshot)
+	}
+	return ctrl.syncReadyGroupSnapshot(groupSnapshot)
+}
+
+// syncReadyGroupSnapshot checks the group snapshot which has been bound to group
+// snapshot content successfully before.
+// If there is any problem with the binding (e.g., group snapshot points to a
+// non-existent group snapshot content), update the group snapshot status and emit event.
+func (ctrl *csiSnapshotCommonController) syncReadyGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) error {
+	if !utils.IsBoundVolumeGroupSnapshotContentNameSet(groupSnapshot) {
+		return fmt.Errorf("group snapshot %s is not bound to a group snapshot content", utils.GroupSnapshotKey(groupSnapshot))
+	}
+	groupSnapshotContent, err := ctrl.getGroupSnapshotContentFromStore(*groupSnapshot.Status.BoundVolumeGroupSnapshotContentName)
+	if err != nil {
+		return nil
+	}
+	if groupSnapshotContent == nil {
+		// this meant there is no matching group snapshot content in cache found
+		// update status of the group snapshot and return
+		return ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMissing", "VolumeGroupSnapshotContent is missing")
+	}
+	klog.V(5).Infof("syncReadyGroupSnapshot[%s]: VolumeGroupSnapshotContent %q found", utils.GroupSnapshotKey(groupSnapshot), groupSnapshotContent.Name)
+	// check binding from group snapshot content side to make sure the binding is still valid
+	if !utils.IsVolumeGroupSnapshotRefSet(groupSnapshot, groupSnapshotContent) {
+		// group snapshot is bound but group snapshot content is not pointing to the group snapshot
+		return ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotMisbound", "VolumeGroupSnapshotContent is not bound to the VolumeGroupSnapshot correctly")
+	}
+
+	// everything is verified, return
+	return nil
+}
+
+// getGroupSnapshotContentFromStore tries to find a VolumeGroupSnapshotContent from group
+// snapshot content cache store by name.
+// Note that if no VolumeGroupSnapshotContent exists in the cache store and no error
+// encountered, it returns (nil, nil)
+func (ctrl *csiSnapshotCommonController) getGroupSnapshotContentFromStore(contentName string) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	obj, exist, err := ctrl.groupSnapshotContentStore.GetByKey(contentName)
+	if err != nil {
+		// should never reach here based on implementation at:
+		// https://github.com/kubernetes/client-go/blob/master/tools/cache/store.go#L226
+		return nil, err
+	}
+	if !exist {
+		// not able to find a matching group snapshot content
+		return nil, nil
+	}
+	groupSnapshotContent, ok := obj.(*crdv1alpha1.VolumeGroupSnapshotContent)
+	if !ok {
+		return nil, fmt.Errorf("expected VolumeGroupSnapshotContent, got %+v", obj)
+	}
+	return groupSnapshotContent, nil
+}
+
+// syncUnreadyGroupSnapshot is the main controller method to decide what to do
+// with a group snapshot which is not set to ready.
+func (ctrl *csiSnapshotCommonController) syncUnreadyGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) error {
+	uniqueGroupSnapshotName := utils.GroupSnapshotKey(groupSnapshot)
+	klog.V(5).Infof("syncUnreadyGroupSnapshot %s", uniqueGroupSnapshotName)
+	/*
+		TODO: Add metrics
+	*/
+
+	// Pre-provisioned snapshot
+	if groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName != nil {
+		groupSnapshotContent, err := ctrl.getPreprovisionedGroupSnapshotContentFromStore(groupSnapshot)
+		if err != nil {
+			return err
+		}
+
+		// if no group snapshot content found yet, update status and return
+		if groupSnapshotContent == nil {
+			// can not find the desired VolumeGroupSnapshotContent from cache store
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMissing", "VolumeGroupSnapshotContent is missing")
+			klog.V(4).Infof("syncUnreadyGroupSnapshot[%s]: group snapshot content %q requested but not found, will try again", utils.GroupSnapshotKey(groupSnapshot), *groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName)
+
+			return fmt.Errorf("group snapshot %s requests an non-existing group snapshot content %s", utils.GroupSnapshotKey(groupSnapshot), *groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName)
+		}
+
+		// Set VolumeGroupSnapshotRef UID
+		newGroupSnapshotContent, err := ctrl.checkAndBindGroupSnapshotContent(groupSnapshot, groupSnapshotContent)
+		if err != nil {
+			// group snapshot is bound but group snapshot content is not bound to group snapshot correctly
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotBindFailed", fmt.Sprintf("GroupSnapshot failed to bind VolumeGroupSnapshotContent, %v", err))
+			return fmt.Errorf("group snapshot %s is bound, but VolumeGroupSnapshotContent %s is not bound to the VolumeGroupSnapshot correctly, %v", uniqueGroupSnapshotName, groupSnapshotContent.Name, err)
+		}
+
+		// update group snapshot status
+		klog.V(5).Infof("syncUnreadyGroupSnapshot [%s]: trying to update group snapshot status", utils.GroupSnapshotKey(groupSnapshot))
+		if _, err = ctrl.updateGroupSnapshotStatus(groupSnapshot, newGroupSnapshotContent); err != nil {
+			// update group snapshot status failed
+			klog.V(4).Infof("failed to update group snapshot %s status: %v", utils.GroupSnapshotKey(groupSnapshot), err)
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, false, v1.EventTypeWarning, "GroupSnapshotStatusUpdateFailed", fmt.Sprintf("GroupSnapshot status update failed, %v", err))
+			return err
+		}
+
+		return nil
+	}
+
+	// groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName == nil - dynamically created group snapshot
+	klog.V(5).Infof("getDynamicallyProvisionedGroupContentFromStore for snapshot %s", uniqueGroupSnapshotName)
+	contentObj, err := ctrl.getDynamicallyProvisionedGroupContentFromStore(groupSnapshot)
+	if err != nil {
+		klog.V(4).Infof("getDynamicallyProvisionedGroupContentFromStore[%s]: error when getting group snapshot content for group snapshot %v", uniqueGroupSnapshotName, err)
+		return err
+	}
+
+	if contentObj != nil {
+		klog.V(5).Infof("Found VolumeGroupSnapshotContent object %s for group snapshot %s", contentObj.Name, uniqueGroupSnapshotName)
+		if contentObj.Spec.Source.VolumeGroupSnapshotHandle != nil {
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotHandleSet", fmt.Sprintf("GroupSnapshot handle should not be set in group snapshot content %s for dynamic provisioning", uniqueGroupSnapshotName))
+			return fmt.Errorf("VolumeGroupSnapshotHandle should not be set in the group snapshot content for dynamic provisioning for group snapshot %s", uniqueGroupSnapshotName)
+		}
+
+		newGroupSnapshot, err := ctrl.bindandUpdateVolumeGroupSnapshot(contentObj, groupSnapshot)
+		if err != nil {
+			klog.V(4).Infof("bindandUpdateVolumeGroupSnapshot[%s]: failed to bind group snapshot content [%s] to group snapshot %v", uniqueGroupSnapshotName, contentObj.Name, err)
+			return err
+		}
+		klog.V(5).Infof("bindandUpdateVolumeGroupSnapshot %v", newGroupSnapshot)
+		return nil
+	}
+
+	// If we reach here, it is a dynamically provisioned group snapshot, and the VolumeGroupSnapshotContent object is not yet created.
+	var groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent
+	if groupSnapshotContent, err = ctrl.createGroupSnapshotContent(groupSnapshot); err != nil {
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentCreationFailed", fmt.Sprintf("failed to create group snapshot content with error %v", err))
+		return err
+	}
+
+	// Update group snapshot status with BoundVolumeGroupSnapshotContentName
+	klog.V(5).Infof("syncUnreadyGroupSnapshot [%s]: trying to update group snapshot status", utils.GroupSnapshotKey(groupSnapshot))
+	if _, err = ctrl.updateGroupSnapshotStatus(groupSnapshot, groupSnapshotContent); err != nil {
+		// update group snapshot status failed
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, false, v1.EventTypeWarning, "GroupSnapshotStatusUpdateFailed", fmt.Sprintf("GroupSnapshot status update failed, %v", err))
+		return err
+	}
+	return nil
+}
+
+// getPreprovisionedGroupSnapshotContentFromStore tries to find a pre-provisioned
+// volume group snapshot content object from group snapshot content cache store
+// for the passed in VolumeGroupSnapshot.
+// Note that this function assumes the passed in VolumeGroupSnapshot is a pre-provisioned
+// one, i.e., groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName != nil.
+// If no matching group snapshot content is found, it returns (nil, nil).
+// If it found a group snapshot content which is not a pre-provisioned one, it
+// updates the status of the group snapshot with an event and returns an error.
+// If it found a group snapshot content which does not point to the passed in
+// VolumeGroupSnapshot, it updates the status of the group snapshot with an event
+// and returns an error.
+// Otherwise, the found group snapshot content will be returned.
+func (ctrl *csiSnapshotCommonController) getPreprovisionedGroupSnapshotContentFromStore(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	contentName := *groupSnapshot.Spec.Source.VolumeGroupSnapshotContentName
+	if contentName == "" {
+		return nil, fmt.Errorf("empty VolumeGroupSnapshotContentName for group snapshot %s", utils.GroupSnapshotKey(groupSnapshot))
+	}
+	groupSnapshotContent, err := ctrl.getGroupSnapshotContentFromStore(contentName)
+	if err != nil {
+		return nil, err
+	}
+	if groupSnapshotContent == nil {
+		// can not find the desired VolumeGroupSnapshotContent from cache store
+		return nil, nil
+	}
+	// check whether the content is a pre-provisioned VolumeGroupSnapshotContent
+	if groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle == nil {
+		// found a group snapshot content which represents a dynamically provisioned group snapshot
+		// update the group snapshot and return an error
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMismatch", "VolumeGroupSnapshotContent is dynamically provisioned while expecting a pre-provisioned one")
+		klog.V(4).Infof("sync group snapshot[%s]: group snapshot content %q is dynamically provisioned while expecting a pre-provisioned one", utils.GroupSnapshotKey(groupSnapshot), contentName)
+		return nil, fmt.Errorf("group snapshot %s expects a pre-provisioned VolumeGroupSnapshotContent %s but gets a dynamically provisioned one", utils.GroupSnapshotKey(groupSnapshot), contentName)
+	}
+	// verify the group snapshot content points back to the group snapshot
+	ref := groupSnapshotContent.Spec.VolumeGroupSnapshotRef
+	if ref.Name != groupSnapshot.Name || ref.Namespace != groupSnapshot.Namespace || (ref.UID != "" && ref.UID != groupSnapshot.UID) {
+		klog.V(4).Infof("sync group snapshot[%s]: VolumeGroupSnapshotContent %s is bound to another group snapshot %v", utils.GroupSnapshotKey(groupSnapshot), contentName, ref)
+		msg := fmt.Sprintf("VolumeGroupSnapshotContent [%s] is bound to a different group snapshot", contentName)
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMisbound", msg)
+		return nil, fmt.Errorf(msg)
+	}
+	return groupSnapshotContent, nil
+}
+
+// checkandBindGroupSnapshotContent checks whether the VolumeGroupSnapshotRef in
+// the group snapshot content matches the given group snapshot. If match, it binds
+// the group snapshot content with the group snapshot. This is for static binding where
+// user has specified group snapshot name but not UID of the group snapshot in
+// groupSnapshotContent.Spec.VolumeGroupSnapshotRef.
+func (ctrl *csiSnapshotCommonController) checkAndBindGroupSnapshotContent(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot, groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	if groupSnapshotContent.Spec.VolumeGroupSnapshotRef.Name != groupSnapshot.Name {
+		return nil, fmt.Errorf("Could not bind group snapshot %s and group snapshot content %s, the VolumeGroupSnapshotRef does not match", groupSnapshot.Name, groupSnapshotContent.Name)
+	} else if groupSnapshotContent.Spec.VolumeGroupSnapshotRef.UID != "" && groupSnapshotContent.Spec.VolumeGroupSnapshotRef.UID != groupSnapshot.UID {
+		return nil, fmt.Errorf("Could not bind group snapshot %s and group snapshot content %s, the VolumeGroupSnapshotRef does not match", groupSnapshot.Name, groupSnapshotContent.Name)
+	} else if groupSnapshotContent.Spec.VolumeGroupSnapshotRef.UID != "" && groupSnapshotContent.Spec.VolumeGroupSnapshotClassName != nil {
+		return groupSnapshotContent, nil
+	}
+
+	patches := []utils.PatchOp{
+		{
+			Op:    "replace",
+			Path:  "/spec/volumeGroupSnapshotRef/uid",
+			Value: string(groupSnapshot.UID),
+		},
+	}
+	if groupSnapshot.Spec.VolumeGroupSnapshotClassName != nil {
+		className := *(groupSnapshot.Spec.VolumeGroupSnapshotClassName)
+		patches = append(patches, utils.PatchOp{
+			Op:    "replace",
+			Path:  "/spec/volumeGroupSnapshotClassName",
+			Value: className,
+		})
+	}
+
+	newContent, err := utils.PatchVolumeGroupSnapshotContent(groupSnapshotContent, patches, ctrl.clientset)
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshotContent[%s] error status failed %v", groupSnapshotContent.Name, err)
+		return groupSnapshotContent, err
+	}
+
+	_, err = ctrl.storeGroupSnapshotContentUpdate(newContent)
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshotContent[%s] error status: cannot update internal cache %v", newContent.Name, err)
+		return newContent, err
+	}
+	return newContent, nil
+}
+
+// updateGroupSnapshotStatus updates group snapshot status based on group snapshot content status
+func (ctrl *csiSnapshotCommonController) updateGroupSnapshotStatus(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot, groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshot, error) {
+	klog.V(5).Infof("updateGroupSnapshotStatus[%s]", utils.GroupSnapshotKey(groupSnapshot))
+
+	boundContentName := groupSnapshotContent.Name
+	var createdAt *time.Time
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.CreationTime != nil {
+		unixTime := time.Unix(0, *groupSnapshotContent.Status.CreationTime)
+		createdAt = &unixTime
+	}
+	var readyToUse bool
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.ReadyToUse != nil {
+		readyToUse = *groupSnapshotContent.Status.ReadyToUse
+	}
+	var volumeSnapshotErr *crdv1.VolumeSnapshotError
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.Error != nil {
+		volumeSnapshotErr = groupSnapshotContent.Status.Error.DeepCopy()
+	}
+
+	var volumeSnapshotRefList []v1.ObjectReference
+	if groupSnapshotContent.Status != nil && len(groupSnapshotContent.Status.VolumeSnapshotContentRefList) != 0 {
+		for _, contentRef := range groupSnapshotContent.Status.VolumeSnapshotContentRefList {
+			groupSnapshotContent, err := ctrl.contentLister.Get(contentRef.Name)
+			if err != nil {
+				return nil, fmt.Errorf("failed to get group snapshot content %s from group snapshot content store: %v", contentRef.Name, err)
+			}
+			volumeSnapshotRefList = append(volumeSnapshotRefList, groupSnapshotContent.Spec.VolumeSnapshotRef)
+		}
+	}
+
+	klog.V(5).Infof("updateGroupSnapshotStatus: updating VolumeGroupSnapshot [%+v] based on VolumeGroupSnapshotContentStatus [%+v]", groupSnapshot, groupSnapshotContent.Status)
+
+	groupSnapshotObj, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshots(groupSnapshot.Namespace).Get(context.TODO(), groupSnapshot.Name, metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("error get group snapshot %s from api server: %v", utils.GroupSnapshotKey(groupSnapshot), err)
+	}
+
+	var newStatus *crdv1alpha1.VolumeGroupSnapshotStatus
+	updated := false
+	if groupSnapshotObj.Status == nil {
+		newStatus = &crdv1alpha1.VolumeGroupSnapshotStatus{
+			BoundVolumeGroupSnapshotContentName: &boundContentName,
+			ReadyToUse:                          &readyToUse,
+		}
+		if createdAt != nil {
+			newStatus.CreationTime = &metav1.Time{Time: *createdAt}
+		}
+		if volumeSnapshotErr != nil {
+			newStatus.Error = volumeSnapshotErr
+		}
+		if len(volumeSnapshotRefList) == 0 {
+			newStatus.VolumeSnapshotRefList = volumeSnapshotRefList
+		}
+
+		updated = true
+	} else {
+		newStatus = groupSnapshotObj.Status.DeepCopy()
+		if newStatus.BoundVolumeGroupSnapshotContentName == nil {
+			newStatus.BoundVolumeGroupSnapshotContentName = &boundContentName
+			updated = true
+		}
+		if newStatus.CreationTime == nil && createdAt != nil {
+			newStatus.CreationTime = &metav1.Time{Time: *createdAt}
+			updated = true
+		}
+		if newStatus.ReadyToUse == nil || *newStatus.ReadyToUse != readyToUse {
+			newStatus.ReadyToUse = &readyToUse
+			updated = true
+			if readyToUse && newStatus.Error != nil {
+				newStatus.Error = nil
+			}
+		}
+		if (newStatus.Error == nil && volumeSnapshotErr != nil) || (newStatus.Error != nil && volumeSnapshotErr != nil && newStatus.Error.Time != nil && volumeSnapshotErr.Time != nil && &newStatus.Error.Time != &volumeSnapshotErr.Time) || (newStatus.Error != nil && volumeSnapshotErr == nil) {
+			newStatus.Error = volumeSnapshotErr
+			updated = true
+		}
+		if len(newStatus.VolumeSnapshotRefList) == 0 {
+			newStatus.VolumeSnapshotRefList = volumeSnapshotRefList
+			updated = true
+		}
+	}
+
+	if updated {
+		groupSnapshotClone := groupSnapshotObj.DeepCopy()
+		groupSnapshotClone.Status = newStatus
+
+		// Must meet the following criteria to emit a successful CreateGroupSnapshot status
+		// 1. Previous status was nil OR Previous status had a nil CreationTime
+		// 2. New status must be non-nil with a non-nil CreationTime
+		if !utils.IsGroupSnapshotCreated(groupSnapshotObj) && utils.IsGroupSnapshotCreated(groupSnapshotClone) {
+			msg := fmt.Sprintf("GroupSnapshot %s was successfully created by the CSI driver.", utils.GroupSnapshotKey(groupSnapshot))
+			ctrl.eventRecorder.Event(groupSnapshot, v1.EventTypeNormal, "GroupSnapshotCreated", msg)
+		}
+
+		// Must meet the following criteria to emit a successful CreateGroupSnapshotAndReady status
+		// 1. Previous status was nil OR Previous status had a nil ReadyToUse OR Previous status had a false ReadyToUse
+		// 2. New status must be non-nil with a ReadyToUse as true
+		if !utils.IsGroupSnapshotReady(groupSnapshotObj) && utils.IsGroupSnapshotReady(groupSnapshotClone) {
+			msg := fmt.Sprintf("GroupSnapshot %s is ready to use.", utils.GroupSnapshotKey(groupSnapshot))
+			ctrl.eventRecorder.Event(groupSnapshot, v1.EventTypeNormal, "GroupSnapshotReady", msg)
+		}
+
+		newGroupSnapshotObj, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshots(groupSnapshotClone.Namespace).UpdateStatus(context.TODO(), groupSnapshotClone, metav1.UpdateOptions{})
+		if err != nil {
+			return nil, newControllerUpdateError(utils.GroupSnapshotKey(groupSnapshot), err.Error())
+		}
+
+		return newGroupSnapshotObj, nil
+	}
+
+	return groupSnapshotObj, nil
+}
+
+// getDynamicallyProvisionedGroupContentFromStore tries to find a dynamically created
+// group snapshot content object for the passed in VolumeGroupSnapshot from the
+// group snapshot content store.
+// Note that this function assumes the passed in VolumeGroupSnapshot is a dynamic
+// one which requests creating a group snapshot from a group of PVCs.
+// If no matching VolumeGroupSnapshotContent exists in the group snapshot content
+// cache store, it returns (nil, nil)
+// If a group snapshot content is found but it's not dynamically provisioned,
+// the passed in group snapshot status will be updated with an error along with
+// an event, and an error will be returned.
+// If a group snapshot content is found but it does not point to the passed in VolumeGroupSnapshot,
+// the passed in group snapshot will be updated with an error along with an event,
+// and an error will be returned.
+func (ctrl *csiSnapshotCommonController) getDynamicallyProvisionedGroupContentFromStore(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	contentName := utils.GetDynamicSnapshotContentNameForGroupSnapshot(groupSnapshot)
+	groupSnapshotContent, err := ctrl.getGroupSnapshotContentFromStore(contentName)
+	if err != nil {
+		return nil, err
+	}
+	if groupSnapshotContent == nil {
+		// no matching group snapshot content with the desired name has been found in cache
+		return nil, nil
+	}
+	// check whether the group snapshot content represents a dynamically provisioned snapshot
+	if groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle != nil {
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMismatch", "VolumeGroupSnapshotContent "+contentName+" is pre-provisioned while expecting a dynamically provisioned one")
+		klog.V(4).Infof("sync group snapshot[%s]: group snapshot content %s is pre-provisioned while expecting a dynamically provisioned one", utils.GroupSnapshotKey(groupSnapshot), contentName)
+		return nil, fmt.Errorf("group snapshot %s expects a dynamically provisioned VolumeGroupSnapshotContent %s but gets a pre-provisioned one", utils.GroupSnapshotKey(groupSnapshot), contentName)
+	}
+	// check whether the group snapshot content points back to the passed in VolumeGroupSnapshot
+	ref := groupSnapshotContent.Spec.VolumeGroupSnapshotRef
+	// Unlike a pre-provisioned group snapshot content, whose Spec.VolumeGroupSnapshotRef.UID will be
+	// left to be empty to allow binding to a group snapshot, a dynamically provisioned
+	// group snapshot content MUST have its Spec.VolumeGroupSnapshotRef.UID set to the group snapshot's
+	// UID from which it's been created, thus ref.UID == "" is not a legit case here.
+	if ref.Name != groupSnapshot.Name || ref.Namespace != groupSnapshot.Namespace || ref.UID != groupSnapshot.UID {
+		klog.V(4).Infof("sync group snapshot[%s]: VolumeGroupSnapshotContent %s is bound to another group snapshot %v", utils.GroupSnapshotKey(groupSnapshot), contentName, ref)
+		msg := fmt.Sprintf("VolumeGroupSnapshotContent [%s] is bound to a different group snapshot", contentName)
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, true, v1.EventTypeWarning, "GroupSnapshotContentMisbound", msg)
+		return nil, fmt.Errorf(msg)
+	}
+	return groupSnapshotContent, nil
+}
+
+// This routine sets snapshot.Spec.Source.VolumeGroupSnapshotContentName
+func (ctrl *csiSnapshotCommonController) bindandUpdateVolumeGroupSnapshot(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent, groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshot, error) {
+	klog.V(5).Infof("bindandUpdateVolumeGroupSnapshot for group snapshot [%s]: groupSnapshotContent [%s]", groupSnapshot.Name, groupSnapshotContent.Name)
+	groupSnapshotObj, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshots(groupSnapshot.Namespace).Get(context.TODO(), groupSnapshot.Name, metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("error get group snapshot %s from api server: %v", utils.GroupSnapshotKey(groupSnapshot), err)
+	}
+
+	// Copy the group snapshot object before updating it
+	groupSnapshotCopy := groupSnapshotObj.DeepCopy()
+	// update group snapshot status
+	var updateGroupSnapshot *crdv1alpha1.VolumeGroupSnapshot
+	klog.V(5).Infof("bindandUpdateVolumeGroupSnapshot [%s]: trying to update group snapshot status", utils.GroupSnapshotKey(groupSnapshotCopy))
+	updateGroupSnapshot, err = ctrl.updateGroupSnapshotStatus(groupSnapshotCopy, groupSnapshotContent)
+	if err == nil {
+		groupSnapshotCopy = updateGroupSnapshot
+	}
+	if err != nil {
+		// update group snapshot status failed
+		klog.V(4).Infof("failed to update group snapshot %s status: %v", utils.GroupSnapshotKey(groupSnapshot), err)
+		ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshotCopy, true, v1.EventTypeWarning, "GroupSnapshotStatusUpdateFailed", fmt.Sprintf("GroupSnapshot status update failed, %v", err))
+		return nil, err
+	}
+
+	_, err = ctrl.storeGroupSnapshotUpdate(groupSnapshotCopy)
+	if err != nil {
+		klog.Errorf("%v", err)
+	}
+
+	klog.V(5).Infof("bindandUpdateVolumeGroupSnapshot for group snapshot completed [%#v]", groupSnapshotCopy)
+	return groupSnapshotCopy, nil
+}
+
+// createGroupSnapshotContent will only be called for dynamic provisioning
+func (ctrl *csiSnapshotCommonController) createGroupSnapshotContent(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	klog.Infof("createSnapshotContent: Creating group snapshot content for groupn snapshot %s through the plugin ...", utils.GroupSnapshotKey(groupSnapshot))
+
+	/*
+		TODO: Add finalizer to group snapshot
+	*/
+
+	groupSnapshotClass, volumes, contentName, err := ctrl.getCreateGroupSnapshotInput(groupSnapshot)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get input parameters to create group snapshot %s: %q", groupSnapshot.Name, err)
+	}
+
+	snapshotRef, err := ref.GetReference(scheme.Scheme, groupSnapshot)
+	if err != nil {
+		return nil, err
+	}
+	var pvNames []string
+	for _, pv := range volumes {
+		pvNames = append(pvNames, pv.Name)
+	}
+
+	groupSnapshotContent := &crdv1alpha1.VolumeGroupSnapshotContent{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: contentName,
+		},
+		Spec: crdv1alpha1.VolumeGroupSnapshotContentSpec{
+			VolumeGroupSnapshotRef: *snapshotRef,
+			Source: crdv1alpha1.VolumeGroupSnapshotContentSource{
+				PersistentVolumeNames: pvNames,
+			},
+			VolumeGroupSnapshotClassName: &(groupSnapshotClass.Name),
+			DeletionPolicy:               groupSnapshotClass.DeletionPolicy,
+			Driver:                       groupSnapshotClass.Driver,
+		},
+	}
+
+	/*
+		TODO: Add secret reference details
+	*/
+
+	var updateGroupSnapshoyContent *crdv1alpha1.VolumeGroupSnapshotContent
+	klog.V(5).Infof("volume group snapshot content %#v", groupSnapshotContent)
+	// Try to create the VolumeGroupSnapshotContent object
+	klog.V(5).Infof("createGroupSnapshotContent [%s]: trying to save volume group snapshot content %s", utils.GroupSnapshotKey(groupSnapshot), groupSnapshotContent.Name)
+	if updateGroupSnapshoyContent, err = ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshotContents().Create(context.TODO(), groupSnapshotContent, metav1.CreateOptions{}); err == nil || apierrs.IsAlreadyExists(err) {
+		// Save succeeded.
+		if err != nil {
+			klog.V(3).Infof("volume group snapshot content %q for group snapshot %q already exists, reusing", groupSnapshotContent.Name, utils.GroupSnapshotKey(groupSnapshot))
+			err = nil
+			updateGroupSnapshoyContent = groupSnapshotContent
+		} else {
+			klog.V(3).Infof("volume group snapshot content %q for group snapshot %q saved, %v", groupSnapshotContent.Name, utils.GroupSnapshotKey(groupSnapshot), groupSnapshotContent)
+		}
+	}
+
+	if err != nil {
+		strerr := fmt.Sprintf("Error creating volume group snapshot content object for group snapshot %s: %v.", utils.GroupSnapshotKey(groupSnapshot), err)
+		klog.Error(strerr)
+		ctrl.eventRecorder.Event(groupSnapshot, v1.EventTypeWarning, "CreateGroupSnapshotContentFailed", strerr)
+		return nil, newControllerUpdateError(utils.GroupSnapshotKey(groupSnapshot), err.Error())
+	}
+
+	msg := fmt.Sprintf("Waiting for a group snapshot %s to be created by the CSI driver.", utils.GroupSnapshotKey(groupSnapshot))
+	ctrl.eventRecorder.Event(groupSnapshot, v1.EventTypeNormal, "CreatingGroupSnapshot", msg)
+
+	// Update group snapshot content in the cache store
+	_, err = ctrl.storeGroupSnapshotContentUpdate(updateGroupSnapshoyContent)
+	if err != nil {
+		klog.Errorf("failed to update group snapshot content store %v", err)
+	}
+
+	return updateGroupSnapshoyContent, nil
+}
+
+func (ctrl *csiSnapshotCommonController) getCreateGroupSnapshotInput(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshotClass, []*v1.PersistentVolume, string, error) {
+	className := groupSnapshot.Spec.VolumeGroupSnapshotClassName
+	klog.V(5).Infof("getCreateGroupSnapshotInput [%s]", groupSnapshot.Name)
+	var groupSnapshotClass *crdv1alpha1.VolumeGroupSnapshotClass
+	var err error
+	if className != nil {
+		groupSnapshotClass, err = ctrl.getGroupSnapshotClass(*className)
+		if err != nil {
+			klog.Errorf("getCreateGroupSnapshotInput failed to getClassFromVolumeGroupSnapshot %s", err)
+			return nil, nil, "", err
+		}
+	} else {
+		klog.Errorf("failed to getCreateGroupSnapshotInput %s without a group snapshot class", groupSnapshot.Name)
+		return nil, nil, "", fmt.Errorf("failed to take group snapshot %s without a group snapshot class", groupSnapshot.Name)
+	}
+
+	volumes, err := ctrl.getVolumesFromVolumeGroupSnapshot(groupSnapshot)
+	if err != nil {
+		klog.Errorf("getCreateGroupSnapshotInput failed to get PersistentVolume objects [%s]: Error: [%#v]", groupSnapshot.Name, err)
+		return nil, nil, "", err
+	}
+
+	// Create VolumeGroupSnapshotContent name
+	contentName := utils.GetDynamicSnapshotContentNameForGroupSnapshot(groupSnapshot)
+
+	return groupSnapshotClass, volumes, contentName, nil
+}
+
+// syncGroupSnapshotContent deals with one key off the queue
+func (ctrl *csiSnapshotCommonController) syncGroupSnapshotContent(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	groupSnapshotName := utils.GroupSnapshotRefKey(&groupSnapshotContent.Spec.VolumeGroupSnapshotRef)
+	klog.V(4).Infof("synchronizing VolumeGroupSnapshotContent[%s]: group snapshot content is bound to group snapshot %s", groupSnapshotContent.Name, groupSnapshotName)
+
+	klog.V(5).Infof("syncGroupSnapshotContent[%s]: check if we should add invalid label on group snapshot content", groupSnapshotContent.Name)
+
+	// Keep this check in the controller since the validation webhook may not have been deployed.
+	if (groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle == nil && len(groupSnapshotContent.Spec.Source.PersistentVolumeNames) == 0) ||
+		(groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle != nil && len(groupSnapshotContent.Spec.Source.PersistentVolumeNames) > 0) {
+		err := fmt.Errorf("Exactly one of VolumeGroupSnapshotHandle and PersistentVolumeNames should be specified")
+		klog.Errorf("syncGroupSnapshotContent[%s]: validation error, %s", groupSnapshotContent.Name, err.Error())
+		ctrl.eventRecorder.Event(groupSnapshotContent, v1.EventTypeWarning, "GroupContentValidationError", err.Error())
+		return err
+	}
+
+	// The VolumeGroupSnapshotContent is reserved for a VolumeGroupSnapshot;
+	// that VolumeGroupSnapshot has not yet been bound to this VolumeGroupSnapshotContent;
+	// syncGroupSnapshot will handle it.
+	if groupSnapshotContent.Spec.VolumeGroupSnapshotRef.UID == "" {
+		klog.V(4).Infof("syncGroupSnapshotContent [%s]: VolumeGroupSnapshotContent is pre-bound to VolumeGroupSnapshot %s", groupSnapshotContent.Name, groupSnapshotName)
+		return nil
+	}
+
+	/*
+		TODO: Add finalizer to prevent deletion
+	*/
+
+	// Check if group snapshot exists in cache store
+	// If getGroupSnapshotFromStore returns (nil, nil), it means group snapshot not found
+	// and it may have already been deleted, and it will fall into the
+	// group snapshot == nil case below
+	var groupSnapshot *crdv1alpha1.VolumeGroupSnapshot
+	groupSnapshot, err := ctrl.getGroupSnapshotFromStore(groupSnapshotName)
+	if err != nil {
+		return err
+	}
+
+	if groupSnapshot != nil && groupSnapshot.UID != groupSnapshotContent.Spec.VolumeGroupSnapshotRef.UID {
+		// The group snapshot that the group snapshot content was pointing to was deleted, and another
+		// with the same name created.
+		klog.V(4).Infof("syncGroupSnapshotContent [%s]: group snapshot %s has different UID, the old one must have been deleted", groupSnapshotContent.Name, groupSnapshotName)
+		// Treat the group snapshot content as bound to a missing snapshot.
+		groupSnapshot = nil
+	} else {
+		// Check if groupSnapshot.Status is different from groupSnapshotContent.Status
+		// and add group snapshot to queue if there is a difference and it is worth
+		// triggering a group snapshot status update.
+		if groupSnapshot != nil && ctrl.needsUpdateGroupSnapshotStatus(groupSnapshot, groupSnapshotContent) {
+			klog.V(4).Infof("synchronizing VolumeGroupSnapshotContent for group snapshot [%s]: update group snapshot status to true if needed.", groupSnapshotName)
+			// Manually trigger a group snapshot status update to happen
+			// right away so that it is in-sync with the group snapshot content status
+			ctrl.groupSnapshotQueue.Add(groupSnapshotName)
+		}
+	}
+	return nil
+}
+
+// getGroupSnapshotFromStore finds group snapshot from the cache store.
+// If getGroupSnapshotFromStore returns (nil, nil), it means group snapshot not
+// found and it may have already been deleted.
+func (ctrl *csiSnapshotCommonController) getGroupSnapshotFromStore(groupSnapshotName string) (*crdv1alpha1.VolumeGroupSnapshot, error) {
+	// Get the VolumeGroupSnapshot by _name_
+	var groupSnapshot *crdv1alpha1.VolumeGroupSnapshot
+	obj, found, err := ctrl.groupSnapshotStore.GetByKey(groupSnapshotName)
+	if err != nil {
+		return nil, err
+	}
+	if !found {
+		klog.V(4).Infof("getGroupSnapshotFromStore: group snapshot %s not found", groupSnapshotName)
+		// Fall through with group snapshot = nil
+		return nil, nil
+	}
+	var ok bool
+	groupSnapshot, ok = obj.(*crdv1alpha1.VolumeGroupSnapshot)
+	if !ok {
+		return nil, fmt.Errorf("cannot convert object from group snapshot cache to group snapshot %q!?: %#v", groupSnapshotName, obj)
+	}
+	klog.V(4).Infof("getGroupSnapshotFromStore: group snapshot %s found", groupSnapshotName)
+
+	return groupSnapshot, nil
+}
+
+// needsUpdateGroupSnapshotStatus compares group snapshot status with the group snapshot content
+// status and decide if group snapshot status needs to be updated based on group snapshot content
+// status
+func (ctrl *csiSnapshotCommonController) needsUpdateGroupSnapshotStatus(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot, groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) bool {
+	klog.V(5).Infof("needsUpdateGroupSnapshotStatus[%s]", utils.GroupSnapshotKey(groupSnapshot))
+
+	if groupSnapshot.Status == nil && groupSnapshotContent.Status != nil {
+		return true
+	}
+	if groupSnapshotContent.Status == nil {
+		return false
+	}
+	if groupSnapshot.Status.BoundVolumeGroupSnapshotContentName == nil {
+		return true
+	}
+	if groupSnapshot.Status.CreationTime == nil && groupSnapshotContent.Status.CreationTime != nil {
+		return true
+	}
+	if groupSnapshot.Status.ReadyToUse == nil && groupSnapshotContent.Status.ReadyToUse != nil {
+		return true
+	}
+	if groupSnapshot.Status.ReadyToUse != nil && groupSnapshotContent.Status.ReadyToUse != nil && groupSnapshot.Status.ReadyToUse != groupSnapshotContent.Status.ReadyToUse {
+		return true
+	}
+
+	return false
+}

pkg/common-controller/snapshot_controller.go

@@ -1165,6 +1165,7 @@ func (ctrl *csiSnapshotCommonController) updateSnapshotStatus(snapshot *crdv1.Vo
 		updated = true
 	} else {
 		newStatus = snapshotObj.Status.DeepCopy()
+		klog.Infof("Raunak 1 %s", newStatus.VolumeGroupSnapshotName)
 		if newStatus.BoundVolumeSnapshotContentName == nil {
 			newStatus.BoundVolumeSnapshotContentName = &boundContentName
 			updated = true

pkg/common-controller/snapshot_controller_base.go

@@ -20,10 +20,13 @@ import (
 	"fmt"
 	"time"
 
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
 	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
 	clientset "github.com/kubernetes-csi/external-snapshotter/client/v6/clientset/versioned"
-	storageinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumesnapshot/v1"
-	storagelisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumesnapshot/v1"
+	groupsnapshotinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumegroupsnapshot/v1alpha1"
+	snapshotinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumesnapshot/v1"
+	groupsnapshotlisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumegroupsnapshot/v1alpha1"
+	snapshotlisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumesnapshot/v1"
 	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/metrics"
 	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
 
@@ -43,25 +46,35 @@ import (
 )
 
 type csiSnapshotCommonController struct {
-	clientset     clientset.Interface
-	client        kubernetes.Interface
-	eventRecorder record.EventRecorder
-	snapshotQueue workqueue.RateLimitingInterface
-	contentQueue  workqueue.RateLimitingInterface
+	clientset                 clientset.Interface
+	client                    kubernetes.Interface
+	eventRecorder             record.EventRecorder
+	snapshotQueue             workqueue.RateLimitingInterface
+	contentQueue              workqueue.RateLimitingInterface
+	groupSnapshotQueue        workqueue.RateLimitingInterface
+	groupSnapshotContentQueue workqueue.RateLimitingInterface
 
-	snapshotLister       storagelisters.VolumeSnapshotLister
-	snapshotListerSynced cache.InformerSynced
-	contentLister        storagelisters.VolumeSnapshotContentLister
-	contentListerSynced  cache.InformerSynced
-	classLister          storagelisters.VolumeSnapshotClassLister
-	classListerSynced    cache.InformerSynced
-	pvcLister            corelisters.PersistentVolumeClaimLister
-	pvcListerSynced      cache.InformerSynced
-	nodeLister           corelisters.NodeLister
-	nodeListerSynced     cache.InformerSynced
+	snapshotLister                   snapshotlisters.VolumeSnapshotLister
+	snapshotListerSynced             cache.InformerSynced
+	contentLister                    snapshotlisters.VolumeSnapshotContentLister
+	contentListerSynced              cache.InformerSynced
+	classLister                      snapshotlisters.VolumeSnapshotClassLister
+	classListerSynced                cache.InformerSynced
+	pvcLister                        corelisters.PersistentVolumeClaimLister
+	pvcListerSynced                  cache.InformerSynced
+	nodeLister                       corelisters.NodeLister
+	nodeListerSynced                 cache.InformerSynced
+	groupSnapshotLister              groupsnapshotlisters.VolumeGroupSnapshotLister
+	groupSnapshotListerSynced        cache.InformerSynced
+	groupSnapshotContentLister       groupsnapshotlisters.VolumeGroupSnapshotContentLister
+	groupSnapshotContentListerSynced cache.InformerSynced
+	groupSnapshotClassLister         groupsnapshotlisters.VolumeGroupSnapshotClassLister
+	groupSnapshotClassListerSynced   cache.InformerSynced
 
-	snapshotStore cache.Store
-	contentStore  cache.Store
+	snapshotStore             cache.Store
+	contentStore              cache.Store
+	groupSnapshotStore        cache.Store
+	groupSnapshotContentStore cache.Store
 
 	metricsManager metrics.MetricsManager
 
@@ -69,23 +82,30 @@ type csiSnapshotCommonController struct {
 
 	enableDistributedSnapshotting bool
 	preventVolumeModeConversion   bool
+	enableVolumeGroupSnapshots    bool
 }
 
 // NewCSISnapshotController returns a new *csiSnapshotCommonController
 func NewCSISnapshotCommonController(
 	clientset clientset.Interface,
 	client kubernetes.Interface,
-	volumeSnapshotInformer storageinformers.VolumeSnapshotInformer,
-	volumeSnapshotContentInformer storageinformers.VolumeSnapshotContentInformer,
-	volumeSnapshotClassInformer storageinformers.VolumeSnapshotClassInformer,
+	volumeSnapshotInformer snapshotinformers.VolumeSnapshotInformer,
+	volumeSnapshotContentInformer snapshotinformers.VolumeSnapshotContentInformer,
+	volumeSnapshotClassInformer snapshotinformers.VolumeSnapshotClassInformer,
+	volumeGroupSnapshotInformer groupsnapshotinformers.VolumeGroupSnapshotInformer,
+	volumeGroupSnapshotContentInformer groupsnapshotinformers.VolumeGroupSnapshotContentInformer,
+	volumeGroupSnapshotClassInformer groupsnapshotinformers.VolumeGroupSnapshotClassInformer,
 	pvcInformer coreinformers.PersistentVolumeClaimInformer,
 	nodeInformer coreinformers.NodeInformer,
 	metricsManager metrics.MetricsManager,
 	resyncPeriod time.Duration,
 	snapshotRateLimiter workqueue.RateLimiter,
 	contentRateLimiter workqueue.RateLimiter,
+	groupSnapshotRateLimiter workqueue.RateLimiter,
+	groupSnapshotContentRateLimiter workqueue.RateLimiter,
 	enableDistributedSnapshotting bool,
 	preventVolumeModeConversion bool,
+	enableVolumeGroupSnapshots bool,
 ) *csiSnapshotCommonController {
 	broadcaster := record.NewBroadcaster()
 	broadcaster.StartLogging(klog.Infof)
@@ -142,12 +162,52 @@ func NewCSISnapshotCommonController(
 
 	ctrl.preventVolumeModeConversion = preventVolumeModeConversion
 
+	ctrl.enableVolumeGroupSnapshots = enableVolumeGroupSnapshots
+
+	if enableVolumeGroupSnapshots {
+		ctrl.groupSnapshotStore = cache.NewStore(cache.DeletionHandlingMetaNamespaceKeyFunc)
+		ctrl.groupSnapshotContentStore = cache.NewStore(cache.DeletionHandlingMetaNamespaceKeyFunc)
+
+		ctrl.groupSnapshotQueue = workqueue.NewNamedRateLimitingQueue(groupSnapshotRateLimiter, "snapshot-controller-group-snapshot")
+		ctrl.groupSnapshotContentQueue = workqueue.NewNamedRateLimitingQueue(groupSnapshotContentRateLimiter, "snapshot-controller-group-content")
+
+		volumeGroupSnapshotInformer.Informer().AddEventHandlerWithResyncPeriod(
+			cache.ResourceEventHandlerFuncs{
+				AddFunc:    func(obj interface{}) { ctrl.enqueueGroupSnapshotWork(obj) },
+				UpdateFunc: func(oldObj, newObj interface{}) { ctrl.enqueueGroupSnapshotWork(newObj) },
+				DeleteFunc: func(obj interface{}) { ctrl.enqueueGroupSnapshotWork(obj) },
+			},
+			ctrl.resyncPeriod,
+		)
+		ctrl.groupSnapshotLister = volumeGroupSnapshotInformer.Lister()
+		ctrl.groupSnapshotListerSynced = volumeGroupSnapshotInformer.Informer().HasSynced
+
+		volumeGroupSnapshotContentInformer.Informer().AddEventHandlerWithResyncPeriod(
+			cache.ResourceEventHandlerFuncs{
+				AddFunc:    func(obj interface{}) { ctrl.enqueueGroupSnapshotContentWork(obj) },
+				UpdateFunc: func(oldObj, newObj interface{}) { ctrl.enqueueGroupSnapshotContentWork(newObj) },
+				DeleteFunc: func(obj interface{}) { ctrl.enqueueGroupSnapshotContentWork(obj) },
+			},
+			ctrl.resyncPeriod,
+		)
+		ctrl.groupSnapshotContentLister = volumeGroupSnapshotContentInformer.Lister()
+		ctrl.groupSnapshotContentListerSynced = volumeGroupSnapshotContentInformer.Informer().HasSynced
+
+		ctrl.groupSnapshotClassLister = volumeGroupSnapshotClassInformer.Lister()
+		ctrl.groupSnapshotClassListerSynced = volumeGroupSnapshotClassInformer.Informer().HasSynced
+
+	}
+
 	return ctrl
 }
 
 func (ctrl *csiSnapshotCommonController) Run(workers int, stopCh <-chan struct{}) {
 	defer ctrl.snapshotQueue.ShutDown()
 	defer ctrl.contentQueue.ShutDown()
+	if ctrl.enableVolumeGroupSnapshots {
+		defer ctrl.groupSnapshotQueue.ShutDown()
+		defer ctrl.groupSnapshotContentQueue.ShutDown()
+	}
 
 	klog.Infof("Starting snapshot controller")
 	defer klog.Infof("Shutting snapshot controller")
@@ -156,17 +216,24 @@ func (ctrl *csiSnapshotCommonController) Run(workers int, stopCh <-chan struct{}
 	if ctrl.enableDistributedSnapshotting {
 		informersSynced = append(informersSynced, ctrl.nodeListerSynced)
 	}
+	if ctrl.enableVolumeGroupSnapshots {
+		informersSynced = append(informersSynced, []cache.InformerSynced{ctrl.groupSnapshotListerSynced, ctrl.groupSnapshotContentListerSynced, ctrl.groupSnapshotClassListerSynced}...)
+	}
 
 	if !cache.WaitForCacheSync(stopCh, informersSynced...) {
 		klog.Errorf("Cannot sync caches")
 		return
 	}
 
-	ctrl.initializeCaches(ctrl.snapshotLister, ctrl.contentLister)
+	ctrl.initializeCaches()
 
 	for i := 0; i < workers; i++ {
 		go wait.Until(ctrl.snapshotWorker, 0, stopCh)
 		go wait.Until(ctrl.contentWorker, 0, stopCh)
+		if ctrl.enableVolumeGroupSnapshots {
+			go wait.Until(ctrl.groupSnapshotWorker, 0, stopCh)
+			go wait.Until(ctrl.groupSnapshotContentWorker, 0, stopCh)
+		}
 	}
 
 	<-stopCh
@@ -481,8 +548,8 @@ func (ctrl *csiSnapshotCommonController) deleteContent(content *crdv1.VolumeSnap
 // initializeCaches fills all controller caches with initial data from etcd in
 // order to have the caches already filled when first addSnapshot/addContent to
 // perform initial synchronization of the controller.
-func (ctrl *csiSnapshotCommonController) initializeCaches(snapshotLister storagelisters.VolumeSnapshotLister, contentLister storagelisters.VolumeSnapshotContentLister) {
-	snapshotList, err := snapshotLister.List(labels.Everything())
+func (ctrl *csiSnapshotCommonController) initializeCaches() {
+	snapshotList, err := ctrl.snapshotLister.List(labels.Everything())
 	if err != nil {
 		klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
 		return
@@ -494,7 +561,7 @@ func (ctrl *csiSnapshotCommonController) initializeCaches(snapshotLister storage
 		}
 	}
 
-	contentList, err := contentLister.List(labels.Everything())
+	contentList, err := ctrl.contentLister.List(labels.Everything())
 	if err != nil {
 		klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
 		return
@@ -506,5 +573,280 @@ func (ctrl *csiSnapshotCommonController) initializeCaches(snapshotLister storage
 		}
 	}
 
+	if ctrl.enableVolumeGroupSnapshots {
+		groupSnapshotList, err := ctrl.snapshotLister.List(labels.Everything())
+		if err != nil {
+			klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
+			return
+		}
+		for _, groupSnapshot := range groupSnapshotList {
+			groupSnapshotClone := groupSnapshot.DeepCopy()
+			if _, err = ctrl.storeGroupSnapshotUpdate(groupSnapshotClone); err != nil {
+				klog.Errorf("error updating volume group snapshot cache: %v", err)
+			}
+		}
+
+		groupContentList, err := ctrl.contentLister.List(labels.Everything())
+		if err != nil {
+			klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
+			return
+		}
+		for _, groupContent := range groupContentList {
+			groupContentClone := groupContent.DeepCopy()
+			if _, err = ctrl.storeGroupSnapshotContentUpdate(groupContentClone); err != nil {
+				klog.Errorf("error updating volume group snapshot content cache: %v", err)
+			}
+		}
+	}
+
 	klog.V(4).Infof("controller initialized")
 }
+
+// enqueueGroupSnapshotWork adds group snapshot to given work queue.
+func (ctrl *csiSnapshotCommonController) enqueueGroupSnapshotWork(obj interface{}) {
+	// Beware of "xxx deleted" events
+	if unknown, ok := obj.(cache.DeletedFinalStateUnknown); ok && unknown.Obj != nil {
+		obj = unknown.Obj
+	}
+	if groupSnapshot, ok := obj.(*crdv1alpha1.VolumeGroupSnapshot); ok {
+		objName, err := cache.DeletionHandlingMetaNamespaceKeyFunc(groupSnapshot)
+		if err != nil {
+			klog.Errorf("failed to get key from object: %v, %v", err, groupSnapshot)
+			return
+		}
+		klog.V(5).Infof("enqueued %q for sync", objName)
+		ctrl.groupSnapshotQueue.Add(objName)
+	}
+}
+
+// enqueueGroupSnapshotContentWork adds group snapshot content to given work queue.
+func (ctrl *csiSnapshotCommonController) enqueueGroupSnapshotContentWork(obj interface{}) {
+	// Beware of "xxx deleted" events
+	if unknown, ok := obj.(cache.DeletedFinalStateUnknown); ok && unknown.Obj != nil {
+		obj = unknown.Obj
+	}
+	if content, ok := obj.(*crdv1alpha1.VolumeGroupSnapshotContent); ok {
+		objName, err := cache.DeletionHandlingMetaNamespaceKeyFunc(content)
+		if err != nil {
+			klog.Errorf("failed to get key from object: %v, %v", err, content)
+			return
+		}
+		klog.V(5).Infof("enqueued %q for sync", objName)
+		ctrl.groupSnapshotContentQueue.Add(objName)
+	}
+}
+
+// groupSnapshotWorker is the main worker for VolumeGroupSnapshots.
+func (ctrl *csiSnapshotCommonController) groupSnapshotWorker() {
+	keyObj, quit := ctrl.groupSnapshotQueue.Get()
+	if quit {
+		return
+	}
+	defer ctrl.groupSnapshotQueue.Done(keyObj)
+
+	if err := ctrl.syncGroupSnapshotByKey(keyObj.(string)); err != nil {
+		// Rather than wait for a full resync, re-add the key to the
+		// queue to be processed.
+		ctrl.groupSnapshotQueue.AddRateLimited(keyObj)
+		klog.V(4).Infof("Failed to sync group snapshot %q, will retry again: %v", keyObj.(string), err)
+	} else {
+		// Finally, if no error occurs we forget this item so it does not
+		// get queued again until another change happens.
+		ctrl.groupSnapshotQueue.Forget(keyObj)
+	}
+}
+
+// groupSnapshotContentWorker is the main worker for VolumeGroupSnapshotContent.
+func (ctrl *csiSnapshotCommonController) groupSnapshotContentWorker() {
+	keyObj, quit := ctrl.groupSnapshotContentQueue.Get()
+	if quit {
+		return
+	}
+	defer ctrl.groupSnapshotContentQueue.Done(keyObj)
+
+	if err := ctrl.syncGroupSnapshotContentByKey(keyObj.(string)); err != nil {
+		// Rather than wait for a full resync, re-add the key to the
+		// queue to be processed.
+		ctrl.groupSnapshotContentQueue.AddRateLimited(keyObj)
+		klog.V(4).Infof("Failed to sync content %q, will retry again: %v", keyObj.(string), err)
+	} else {
+		// Finally, if no error occurs we Forget this item so it does not
+		// get queued again until another change happens.
+		ctrl.groupSnapshotContentQueue.Forget(keyObj)
+	}
+}
+
+// syncGroupSnapshotByKey processes a VolumeGroupSnapshot request.
+func (ctrl *csiSnapshotCommonController) syncGroupSnapshotByKey(key string) error {
+	klog.V(5).Infof("syncGroupSnapshotByKey[%s]", key)
+
+	namespace, name, err := cache.SplitMetaNamespaceKey(key)
+	klog.V(5).Infof("groupSnapshotWorker: group snapshot namespace [%s] name [%s]", namespace, name)
+	if err != nil {
+		klog.Errorf("error getting namespace & name of group snapshot %q to get group snapshot from informer: %v", key, err)
+		return nil
+	}
+	groupSnapshot, err := ctrl.groupSnapshotLister.VolumeGroupSnapshots(namespace).Get(name)
+	if err == nil {
+		// The volume group snapshot still exists in informer cache, the event must have
+		// been add/update/sync
+		newGroupSnapshot, err := ctrl.checkAndUpdateGroupSnapshotClass(groupSnapshot)
+		if err == nil || (newGroupSnapshot.ObjectMeta.DeletionTimestamp != nil && errors.IsNotFound(err)) {
+			// If the VolumeSnapshotClass is not found, we still need to process an update
+			// so that syncGroupSnapshot can delete the snapshot, should it still exist in the
+			// cluster after it's been removed from the informer cache
+			if newGroupSnapshot.ObjectMeta.DeletionTimestamp != nil && errors.IsNotFound(err) {
+				klog.V(5).Infof("GroupSnapshot %q is being deleted. GroupSnapshotClass has already been removed", key)
+			}
+			klog.V(5).Infof("Updating group snapshot %q", key)
+			return ctrl.updateGroupSnapshot(newGroupSnapshot)
+		}
+		return err
+	}
+	if err != nil && !errors.IsNotFound(err) {
+		klog.V(2).Infof("error getting group snapshot %q from informer: %v", key, err)
+		return err
+	}
+	// The group snapshot is not in informer cache, the event must have been "delete"
+	vgsObj, found, err := ctrl.groupSnapshotStore.GetByKey(key)
+	if err != nil {
+		klog.V(2).Infof("error getting group snapshot %q from cache: %v", key, err)
+		return nil
+	}
+	if !found {
+		// The controller has already processed the delete event and
+		// deleted the group snapshot from its cache
+		klog.V(2).Infof("deletion of group snapshot %q was already processed", key)
+		return nil
+	}
+	groupSnapshot, ok := vgsObj.(*crdv1alpha1.VolumeGroupSnapshot)
+	if !ok {
+		klog.Errorf("expected vgs, got %+v", vgsObj)
+		return nil
+	}
+
+	klog.V(5).Infof("deleting group snapshot %q", key)
+	ctrl.deleteGroupSnapshot(groupSnapshot)
+
+	return nil
+}
+
+// checkAndUpdateGroupSnapshotClass gets the VolumeGroupSnapshotClass from VolumeGroupSnapshot.
+// If it is not set, gets it from default VolumeGroupSnapshotClass and sets it.
+// On error, it must return the original group snapshot, not nil, because the caller
+// syncGroupSnapshotByKey needs to check group snapshot's timestamp.
+func (ctrl *csiSnapshotCommonController) checkAndUpdateGroupSnapshotClass(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) (*crdv1alpha1.VolumeGroupSnapshot, error) {
+	className := groupSnapshot.Spec.VolumeGroupSnapshotClassName
+	var class *crdv1alpha1.VolumeGroupSnapshotClass
+	var err error
+	newGroupSnapshot := groupSnapshot
+	if className != nil {
+		klog.V(5).Infof("checkAndUpdateGroupSnapshotClass [%s]: VolumeGroupSnapshotClassName [%s]", groupSnapshot.Name, *className)
+		class, err = ctrl.getGroupSnapshotClass(*className)
+		if err != nil {
+			klog.Errorf("checkAndUpdateGroupSnapshotClass failed to getGroupSnapshotClass %v", err)
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, false, v1.EventTypeWarning, "GetGroupSnapshotClassFailed", fmt.Sprintf("failed to get group snapshot class with error %v", err))
+			// we need to return the original group snapshot even if the class isn't found, as it may need to be deleted
+			return newGroupSnapshot, err
+		}
+	} else {
+		klog.V(5).Infof("checkAndUpdateGroupSnapshotClass [%s]: SetDefaultGroupSnapshotClass", groupSnapshot.Name)
+		class, newGroupSnapshot, err = ctrl.SetDefaultGroupSnapshotClass(groupSnapshot)
+		if err != nil {
+			klog.Errorf("checkAndUpdateGroupSnapshotClass failed to setDefaultClass %v", err)
+			ctrl.updateGroupSnapshotErrorStatusWithEvent(groupSnapshot, false, v1.EventTypeWarning, "SetDefaultGroupSnapshotClassFailed", fmt.Sprintf("Failed to set default group snapshot class with error %v", err))
+			return groupSnapshot, err
+		}
+	}
+
+	// For pre-provisioned group snapshots, we may not have group snapshot class
+	if class != nil {
+		klog.V(5).Infof("VolumeGroupSnapshotClass [%s] Driver [%s]", class.Name, class.Driver)
+	}
+	return newGroupSnapshot, nil
+}
+
+// syncGroupSnapshotContentByKey processes a VolumeGroupSnapshotContent request.
+func (ctrl *csiSnapshotCommonController) syncGroupSnapshotContentByKey(key string) error {
+	klog.V(5).Infof("syncGroupSnapshotContentByKey[%s]", key)
+
+	_, name, err := cache.SplitMetaNamespaceKey(key)
+	if err != nil {
+		klog.V(4).Infof("error getting name of groupSnapshotContent %q to get groupSnapshotContent from informer: %v", key, err)
+		return nil
+	}
+	content, err := ctrl.groupSnapshotContentLister.Get(name)
+	// The content still exists in informer cache, the event must have
+	// been add/update/sync
+	if err == nil {
+		// If error occurs we add this item back to the queue
+		return ctrl.updateGroupSnapshotContent(content)
+	}
+	if !errors.IsNotFound(err) {
+		klog.V(2).Infof("error getting group snapshot content %q from informer: %v", key, err)
+		return nil
+	}
+
+	// The group snapshot content is not in informer cache, the event must have been "delete"
+	contentObj, found, err := ctrl.groupSnapshotContentStore.GetByKey(key)
+	if err != nil {
+		klog.V(2).Infof("error getting group snapshot content %q from cache: %v", key, err)
+		return nil
+	}
+	if !found {
+		// The controller has already processed the delete event and
+		// deleted the group snapshot content from its cache
+		klog.V(2).Infof("deletion of group snapshot content %q was already processed", key)
+		return nil
+	}
+	content, ok := contentObj.(*crdv1alpha1.VolumeGroupSnapshotContent)
+	if !ok {
+		klog.Errorf("expected group snapshot content, got %+v", content)
+		return nil
+	}
+	ctrl.deleteGroupSnapshotContent(content)
+	return nil
+}
+
+// updateGroupSnapshotContent runs in worker thread and handles "groupsnapshotcontent added",
+// "groupsnapshotcontent updated" and "periodic sync" events.
+func (ctrl *csiSnapshotCommonController) updateGroupSnapshotContent(content *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	// Store the new group snapshot content version in the cache and do not process
+	// it if this is an old version.
+	new, err := ctrl.storeGroupSnapshotContentUpdate(content)
+	if err != nil {
+		klog.Errorf("%v", err)
+	}
+	if !new {
+		return nil
+	}
+	err = ctrl.syncGroupSnapshotContent(content)
+	if err != nil {
+		if errors.IsConflict(err) {
+			// Version conflict error happens quite often and the controller
+			// recovers from it easily.
+			klog.V(3).Infof("could not sync group snapshot content %q: %+v", content.Name, err)
+		} else {
+			klog.Errorf("could not sync group snapshot content %q: %+v", content.Name, err)
+		}
+		return err
+	}
+	return nil
+}
+
+// deleteGroupSnapshotContent runs in worker thread and handles "groupsnapshotcontent deleted" event.
+func (ctrl *csiSnapshotCommonController) deleteGroupSnapshotContent(content *crdv1alpha1.VolumeGroupSnapshotContent) {
+	_ = ctrl.contentStore.Delete(content)
+	klog.V(4).Infof("group snapshot content %q deleted", content.Name)
+
+	groupSnapshotName := utils.GroupSnapshotRefKey(&content.Spec.VolumeGroupSnapshotRef)
+	if groupSnapshotName == "" {
+		klog.V(5).Infof("deleteGroupContent[%q]: group snapshot content not bound", content.Name)
+		return
+	}
+	// sync the group snapshot when its group snapshot content is deleted. Explicitly
+	// sync'ing the group snapshot here in response to group snapshot content deletion
+	// prevents the group snapshot from waiting until the next sync period for its release.
+	klog.V(5).Infof("deleteGroupContent[%q]: scheduling sync of group snapshot %s", content.Name, groupSnapshotName)
+	ctrl.groupSnapshotQueue.Add(groupSnapshotName)
+}

pkg/group_snapshotter/group_snapshotter.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package group_snapshotter
+
+import (
+	"context"
+	"github.com/container-storage-interface/spec/lib/go/csi"
+	csirpc "github.com/kubernetes-csi/csi-lib-utils/rpc"
+	"google.golang.org/grpc"
+	klog "k8s.io/klog/v2"
+	"time"
+)
+
+// GroupSnapshotter implements CreateGroupSnapshot/DeleteGroupSnapshot operations against a CSI driver.
+type GroupSnapshotter interface {
+	// CreateGroupSnapshot creates a group snapshot for multiple volumes
+	CreateGroupSnapshot(ctx context.Context, groupSnapshotName string, volumeIDs []string, parameters map[string]string, snapshotterCredentials map[string]string) (driverName string, groupSnapshotId string, snapshots []*csi.Snapshot, timestamp time.Time, readyToUse bool, err error)
+
+	// DeleteGroupSnapshot deletes a group snapshot of multiple volumes
+	DeleteGroupSnapshot(ctx context.Context, groupSnapshotID string, snapshotterCredentials map[string]string) (err error)
+
+	// GetGroupSnapshotStatus returns if a group snapshot is ready to use, its creation time, etc
+	GetGroupSnapshotStatus(ctx context.Context, groupSnapshotID string, snapshotterListCredentials map[string]string) (bool, time.Time, error)
+}
+
+type groupSnapshot struct {
+	conn *grpc.ClientConn
+}
+
+func NewGroupSnapshotter(conn *grpc.ClientConn) GroupSnapshotter {
+	return &groupSnapshot{
+		conn: conn,
+	}
+}
+
+func (gs *groupSnapshot) CreateGroupSnapshot(ctx context.Context, groupSnapshotName string, volumeIDs []string, parameters map[string]string, snapshotterCredentials map[string]string) (string, string, []*csi.Snapshot, time.Time, bool, error) {
+	klog.V(5).Infof("CSI CreateGroupSnapshot: %s", groupSnapshotName)
+	client := csi.NewGroupControllerClient(gs.conn)
+
+	driverName, err := csirpc.GetDriverName(ctx, gs.conn)
+	if err != nil {
+		return "", "", nil, time.Time{}, false, err
+	}
+
+	req := csi.CreateVolumeGroupSnapshotRequest{
+		Name:            groupSnapshotName,
+		SourceVolumeIds: volumeIDs,
+		Secrets:         snapshotterCredentials,
+		Parameters:      parameters,
+	}
+
+	rsp, err := client.CreateVolumeGroupSnapshot(ctx, &req)
+	if err != nil {
+		return "", "", nil, time.Time{}, false, err
+	}
+
+	klog.V(5).Infof("CSI CreateGroupSnapshot: %s driver name [%s] group snapshot ID [%s] time stamp [%v] snapshots [%v] readyToUse [%v]", groupSnapshotName, driverName, rsp.GroupSnapshot.GroupSnapshotId, rsp.GroupSnapshot.CreationTime, rsp.GroupSnapshot.Snapshots, rsp.GroupSnapshot.ReadyToUse)
+	creationTime := rsp.GroupSnapshot.CreationTime.AsTime()
+	return driverName, rsp.GroupSnapshot.GroupSnapshotId, rsp.GroupSnapshot.Snapshots, creationTime, rsp.GroupSnapshot.ReadyToUse, nil
+
+}
+
+func (gs *groupSnapshot) DeleteGroupSnapshot(ctx context.Context, groupSnapshotID string, snapshotterCredentials map[string]string) error {
+	// TODO: Implement DeleteGroupSnapshot
+	return nil
+}
+
+func (gs *groupSnapshot) GetGroupSnapshotStatus(ctx context.Context, groupSnapshotID string, snapshotterListCredentials map[string]string) (bool, time.Time, error) {
+	// TODO: Implement GetGroupSnapshotStatus
+	return true, time.Now(), nil
+}

pkg/sidecar-controller/csi_handler.go

@@ -19,6 +19,9 @@ package sidecar_controller
 import (
 	"context"
 	"fmt"
+	"github.com/container-storage-interface/spec/lib/go/csi"
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/group_snapshotter"
 	"strings"
 	"time"
 
@@ -31,28 +34,39 @@ type Handler interface {
 	CreateSnapshot(content *crdv1.VolumeSnapshotContent, parameters map[string]string, snapshotterCredentials map[string]string) (string, string, time.Time, int64, bool, error)
 	DeleteSnapshot(content *crdv1.VolumeSnapshotContent, snapshotterCredentials map[string]string) error
 	GetSnapshotStatus(content *crdv1.VolumeSnapshotContent, snapshotterListCredentials map[string]string) (bool, time.Time, int64, error)
+	CreateGroupSnapshot(content *crdv1alpha1.VolumeGroupSnapshotContent, volumeIDs []string, parameters map[string]string, snapshotterCredentials map[string]string) (string, string, []*csi.Snapshot, time.Time, bool, error)
+	GetGroupSnapshotStatus(content *crdv1alpha1.VolumeGroupSnapshotContent, snapshotterListCredentials map[string]string) (bool, time.Time, error)
 }
 
 // csiHandler is a handler that calls CSI to create/delete volume snapshot.
 type csiHandler struct {
-	snapshotter            snapshotter.Snapshotter
-	timeout                time.Duration
-	snapshotNamePrefix     string
-	snapshotNameUUIDLength int
+	snapshotter                 snapshotter.Snapshotter
+	groupSnapshotter            group_snapshotter.GroupSnapshotter
+	timeout                     time.Duration
+	snapshotNamePrefix          string
+	snapshotNameUUIDLength      int
+	groupSnapshotNamePrefix     string
+	groupSnapshotNameUUIDLength int
 }
 
 // NewCSIHandler returns a handler which includes the csi connection and Snapshot name details
 func NewCSIHandler(
 	snapshotter snapshotter.Snapshotter,
+	groupSnapshotter group_snapshotter.GroupSnapshotter,
 	timeout time.Duration,
 	snapshotNamePrefix string,
 	snapshotNameUUIDLength int,
+	groupSnapshotNamePrefix string,
+	groupSnapshotNameUUIDLength int,
 ) Handler {
 	return &csiHandler{
-		snapshotter:            snapshotter,
-		timeout:                timeout,
-		snapshotNamePrefix:     snapshotNamePrefix,
-		snapshotNameUUIDLength: snapshotNameUUIDLength,
+		snapshotter:                 snapshotter,
+		groupSnapshotter:            groupSnapshotter,
+		timeout:                     timeout,
+		snapshotNamePrefix:          snapshotNamePrefix,
+		snapshotNameUUIDLength:      snapshotNameUUIDLength,
+		groupSnapshotNamePrefix:     groupSnapshotNamePrefix,
+		groupSnapshotNameUUIDLength: groupSnapshotNameUUIDLength,
 	}
 }
 
@@ -131,3 +145,55 @@ func makeSnapshotName(prefix, snapshotUID string, snapshotNameUUIDLength int) (s
 	}
 	return fmt.Sprintf("%s-%s", prefix, strings.Replace(snapshotUID, "-", "", -1)[0:snapshotNameUUIDLength]), nil
 }
+
+func (handler *csiHandler) CreateGroupSnapshot(content *crdv1alpha1.VolumeGroupSnapshotContent, volumeIDs []string, parameters map[string]string, snapshotterCredentials map[string]string) (string, string, []*csi.Snapshot, time.Time, bool, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), handler.timeout)
+	defer cancel()
+
+	if content.Spec.VolumeGroupSnapshotRef.UID == "" {
+		return "", "", nil, time.Time{}, false, fmt.Errorf("cannot create group snapshot. Group snapshot content %s not bound to a group snapshot", content.Name)
+	}
+
+	if len(volumeIDs) == 0 {
+		return "", "", nil, time.Time{}, false, fmt.Errorf("cannot create group snapshot. PVCs to be snapshotted not found in group snapshot content %s", content.Name)
+	}
+
+	groupSnapshotName, err := handler.makeGroupSnapshotName(string(content.Spec.VolumeGroupSnapshotRef.UID))
+	if err != nil {
+		return "", "", nil, time.Time{}, false, err
+	}
+	return handler.groupSnapshotter.CreateGroupSnapshot(ctx, groupSnapshotName, volumeIDs, parameters, snapshotterCredentials)
+}
+
+func (handler *csiHandler) GetGroupSnapshotStatus(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent, snapshotterListCredentials map[string]string) (bool, time.Time, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), handler.timeout)
+	defer cancel()
+
+	var groupSnapshotHandle string
+	var err error
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.VolumeGroupSnapshotHandle != nil {
+		groupSnapshotHandle = *groupSnapshotContent.Status.VolumeGroupSnapshotHandle
+	} else if groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle != nil {
+		groupSnapshotHandle = *groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle
+	} else {
+		return false, time.Time{}, fmt.Errorf("failed to list group snapshot for group snapshot content %s: groupSnapshotHandle is missing", groupSnapshotContent.Name)
+	}
+
+	csiSnapshotStatus, timestamp, err := handler.groupSnapshotter.GetGroupSnapshotStatus(ctx, groupSnapshotHandle, snapshotterListCredentials)
+	if err != nil {
+		return false, time.Time{}, fmt.Errorf("failed to list group snapshot for group snapshot content %s: %q", groupSnapshotContent.Name, err)
+	}
+
+	return csiSnapshotStatus, timestamp, nil
+}
+
+func (handler *csiHandler) makeGroupSnapshotName(groupSnapshotUID string) (string, error) {
+	if len(groupSnapshotUID) == 0 {
+		return "", fmt.Errorf("group snapshot object is missing UID")
+	}
+	if handler.groupSnapshotNameUUIDLength == -1 {
+		return fmt.Sprintf("%s-%s", handler.groupSnapshotNamePrefix, groupSnapshotUID), nil
+	}
+
+	return fmt.Sprintf("%s-%s", handler.groupSnapshotNamePrefix, strings.Replace(groupSnapshotUID, "-", "", -1)[0:handler.groupSnapshotNameUUIDLength]), nil
+}

pkg/sidecar-controller/framework_test.go

@@ -566,12 +566,19 @@ func newTestController(kubeClient kubernetes.Interface, clientset clientset.Inte
 		informerFactory.Snapshot().V1().VolumeSnapshotContents(),
 		informerFactory.Snapshot().V1().VolumeSnapshotClasses(),
 		fakeSnapshot,
+		nil, // TODO: Replace with fake group snapshotter
 		5*time.Millisecond,
 		60*time.Second,
 		"snapshot",
 		-1,
+		"groupsnapshot",
+		-1,
 		true,
 		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
+		false,
+		informerFactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotContents(),
+		informerFactory.Groupsnapshot().V1alpha1().VolumeGroupSnapshotClasses(),
+		workqueue.NewItemExponentialFailureRateLimiter(1*time.Millisecond, 1*time.Minute),
 	)
 
 	ctrl.eventRecorder = record.NewFakeRecorder(1000)

pkg/sidecar-controller/groupsnapshot_helper.go

@@ -0,0 +1,688 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package sidecar_controller
+
+import (
+	"context"
+	"crypto/sha256"
+	"fmt"
+	"time"
+
+	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/tools/cache"
+	klog "k8s.io/klog/v2"
+
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
+)
+
+func (ctrl *csiSnapshotSideCarController) storeGroupSnapshotContentUpdate(groupSnapshotContent interface{}) (bool, error) {
+	return utils.StoreObjectUpdate(ctrl.groupSnapshotContentStore, groupSnapshotContent, "groupsnapshotcontent")
+}
+
+// enqueueGroupSnapshotContentWork adds group snapshot content to given work queue.
+func (ctrl *csiSnapshotSideCarController) enqueueGroupSnapshotContentWork(obj interface{}) {
+	// Beware of "xxx deleted" events
+	if unknown, ok := obj.(cache.DeletedFinalStateUnknown); ok && unknown.Obj != nil {
+		obj = unknown.Obj
+	}
+	if groupSnapshotContent, ok := obj.(*crdv1alpha1.VolumeGroupSnapshotContent); ok {
+		objName, err := cache.DeletionHandlingMetaNamespaceKeyFunc(groupSnapshotContent)
+		if err != nil {
+			klog.Errorf("failed to get key from object: %v, %v", err, groupSnapshotContent)
+			return
+		}
+		klog.V(5).Infof("enqueued %q for sync", objName)
+		ctrl.groupSnapshotContentQueue.Add(objName)
+	}
+}
+
+// groupSnapshotContentWorker processes items from groupSnapshotContentQueue.
+// It must run only once, syncGroupSnapshotContent is not assured to be reentrant.
+func (ctrl *csiSnapshotSideCarController) groupSnapshotContentWorker() {
+	keyObj, quit := ctrl.groupSnapshotContentQueue.Get()
+	if quit {
+		return
+	}
+	defer ctrl.groupSnapshotContentQueue.Done(keyObj)
+
+	if err := ctrl.syncGroupSnapshotContentByKey(keyObj.(string)); err != nil {
+		// Rather than wait for a full resync, re-add the key to the
+		// queue to be processed.
+		ctrl.groupSnapshotContentQueue.AddRateLimited(keyObj)
+		klog.V(4).Infof("Failed to sync group snapshot content %q, will retry again: %v", keyObj.(string), err)
+		return
+	}
+
+	// Finally, if no error occurs we forget this item so it does not
+	// get queued again until another change happens.
+	ctrl.groupSnapshotContentQueue.Forget(keyObj)
+	return
+}
+
+func (ctrl *csiSnapshotSideCarController) syncGroupSnapshotContentByKey(key string) error {
+	klog.V(5).Infof("syncGroupSnapshotContentByKey[%s]", key)
+
+	_, name, err := cache.SplitMetaNamespaceKey(key)
+	if err != nil {
+		klog.V(4).Infof("error getting name of groupSnapshotContent %q from informer: %v", key, err)
+		return nil
+	}
+	groupSnapshotContent, err := ctrl.groupSnapshotContentLister.Get(name)
+	// The group snapshot content still exists in informer cache, the event must
+	// have been add/update/sync
+	if err == nil {
+		if ctrl.isDriverMatch(groupSnapshotContent) {
+			err = ctrl.updateGroupSnapshotContentInInformerCache(groupSnapshotContent)
+		}
+		if err != nil {
+			// If error occurs we add this item back to the queue
+			return err
+		}
+		return nil
+	}
+	if !errors.IsNotFound(err) {
+		klog.V(2).Infof("error getting group snapshot content %q from informer: %v", key, err)
+		return nil
+	}
+
+	// The groupSnapshotContent is not in informer cache, the event must have been
+	// "delete"
+	groupSnapshotContentObj, found, err := ctrl.groupSnapshotContentStore.GetByKey(key)
+	if err != nil {
+		klog.V(2).Infof("error getting group snapshot content %q from cache: %v", key, err)
+		return nil
+	}
+	if !found {
+		// The controller has already processed the delete event and
+		// deleted the group snapshot content from its cache
+		klog.V(2).Infof("deletion of group snapshot content %q was already processed", key)
+		return nil
+	}
+	groupSnapshotContent, ok := groupSnapshotContentObj.(*crdv1alpha1.VolumeGroupSnapshotContent)
+	if !ok {
+		klog.Errorf("expected group snapshot content, got %+v", groupSnapshotContent)
+		return nil
+	}
+	ctrl.deleteGroupSnapshotContentInCacheStore(groupSnapshotContent)
+	return nil
+}
+
+// updateGroupSnapshotContentInInformerCache runs in worker thread and handles
+// "group snapshot content added", "group snapshot content updated" and "periodic
+// sync" events.
+func (ctrl *csiSnapshotSideCarController) updateGroupSnapshotContentInInformerCache(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	// Store the new group snapshot content version in the cache and do not process
+	// it if this is an old version.
+	new, err := ctrl.storeGroupSnapshotContentUpdate(groupSnapshotContent)
+	if err != nil {
+		klog.Errorf("%v", err)
+	}
+	if !new {
+		return nil
+	}
+	err = ctrl.syncGroupSnapshotContent(groupSnapshotContent)
+	if err != nil {
+		if errors.IsConflict(err) {
+			// Version conflict error happens quite often and the controller
+			// recovers from it easily.
+			klog.V(3).Infof("could not sync group snapshot content %q: %+v", groupSnapshotContent.Name, err)
+		} else {
+			klog.Errorf("could not sync group snapshot content %q: %+v", groupSnapshotContent.Name, err)
+		}
+		return err
+	}
+	return nil
+}
+
+// deleteGroupSnapshotContentInCacheStore runs in worker thread and handles "group
+// snapshot content deleted" event.
+func (ctrl *csiSnapshotSideCarController) deleteGroupSnapshotContentInCacheStore(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) {
+	_ = ctrl.groupSnapshotContentStore.Delete(groupSnapshotContent)
+	klog.V(4).Infof("group snapshot content %q deleted", groupSnapshotContent.Name)
+}
+
+// syncGroupSnapshotContent deals with one key off the queue.  It returns false when it's time to quit.
+func (ctrl *csiSnapshotSideCarController) syncGroupSnapshotContent(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	klog.V(5).Infof("synchronizing VolumeGroupSnapshotContent[%s]", groupSnapshotContent.Name)
+
+	/*
+		TODO: Check if the group snapshot content should be deleted
+	*/
+
+	if len(groupSnapshotContent.Spec.Source.PersistentVolumeNames) != 0 && groupSnapshotContent.Status == nil {
+		klog.V(5).Infof("syncGroupSnapshotContent: Call CreateGroupSnapshot for group snapshot content %s", groupSnapshotContent.Name)
+		return ctrl.createGroupSnapshot(groupSnapshotContent)
+	}
+
+	// Skip checkandUpdateGroupSnapshotContentStatus() if ReadyToUse is already
+	// true. We don't want to keep calling CreateGroupSnapshot CSI methods over
+	// and over again for performance reasons.
+	var err error
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.ReadyToUse != nil && *groupSnapshotContent.Status.ReadyToUse == true {
+		// Try to remove AnnVolumeGroupSnapshotBeingCreated if it is not removed yet for some reason
+		_, err = ctrl.removeAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent)
+		return err
+	}
+	return ctrl.checkandUpdateGroupSnapshotContentStatus(groupSnapshotContent)
+}
+
+// createGroupSnapshot starts new asynchronous operation to create group snapshot
+func (ctrl *csiSnapshotSideCarController) createGroupSnapshot(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	klog.V(5).Infof("createGroupSnapshot for group snapshot content [%s]: started", groupSnapshotContent.Name)
+	groupSnapshotContentObj, err := ctrl.createGroupSnapshotWrapper(groupSnapshotContent)
+	if err != nil {
+		ctrl.updateGroupSnapshotContentErrorStatusWithEvent(groupSnapshotContentObj, v1.EventTypeWarning, "GroupSnapshotCreationFailed", fmt.Sprintf("Failed to create group snapshot: %v", err))
+		klog.Errorf("createGroupSnapshot for groupSnapshotContent [%s]: error occurred in createGroupSnapshotWrapper: %v", groupSnapshotContent.Name, err)
+		return err
+	}
+
+	_, updateErr := ctrl.storeGroupSnapshotContentUpdate(groupSnapshotContentObj)
+	if updateErr != nil {
+		// We will get a "group snapshot update" event soon, this is not a big error
+		klog.V(4).Infof("createGroupSnapshot for groupSnapshotContent [%s]: cannot update internal groupSnapshotContent cache: %v", groupSnapshotContent.Name, updateErr)
+	}
+
+	return nil
+}
+
+// This is a wrapper function for the group snapshot creation process.
+func (ctrl *csiSnapshotSideCarController) createGroupSnapshotWrapper(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	klog.Infof("createGroupSnapshotWrapper: Creating group snapshot for group snapshot content %s through the plugin ...", groupSnapshotContent.Name)
+
+	class, snapshotterCredentials, err := ctrl.getCSIGroupSnapshotInput(groupSnapshotContent)
+	if err != nil {
+		return groupSnapshotContent, fmt.Errorf("failed to get input parameters to create group snapshot for group snapshot content %s: %q", groupSnapshotContent.Name, err)
+	}
+
+	// NOTE(xyang): handle create timeout
+	// Add an annotation to indicate the group snapshot creation request has been
+	// sent to the storage system and the controller is waiting for a response.
+	// The annotation will be removed after the storage system has responded with
+	// success or permanent failure. If the request times out, annotation will
+	// remain on the groupSnapshotContent to avoid potential leaking of a group snapshot resource on
+	// the storage system.
+	groupSnapshotContent, err = ctrl.setAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent)
+	if err != nil {
+		return groupSnapshotContent, fmt.Errorf("failed to add VolumeGroupSnapshotBeingCreated annotation on the group snapshot content %s: %q", groupSnapshotContent.Name, err)
+	}
+
+	parameters, err := utils.RemovePrefixedParameters(class.Parameters)
+	if err != nil {
+		return groupSnapshotContent, fmt.Errorf("failed to remove CSI Parameters of prefixed keys: %v", err)
+	}
+	if ctrl.extraCreateMetadata {
+		parameters[utils.PrefixedVolumeGroupSnapshotNameKey] = groupSnapshotContent.Spec.VolumeGroupSnapshotRef.Name
+		parameters[utils.PrefixedVolumeGroupSnapshotNamespaceKey] = groupSnapshotContent.Spec.VolumeGroupSnapshotRef.Namespace
+		parameters[utils.PrefixedVolumeGroupSnapshotContentNameKey] = groupSnapshotContent.Name
+	}
+
+	volumeIDs, uuidMap, err := ctrl.getGroupSnapshotVolumeIDs(groupSnapshotContent)
+	driverName, groupSnapshotID, snapshots, creationTime, readyToUse, err := ctrl.handler.CreateGroupSnapshot(groupSnapshotContent, volumeIDs, parameters, snapshotterCredentials)
+	if err != nil {
+		// NOTE(xyang): handle create timeout
+		// If it is a final error, remove annotation to indicate
+		// storage system has responded with an error
+		klog.Infof("createGroupSnapshotWrapper: CreateGroupSnapshot for groupSnapshotContent %s returned error: %v", groupSnapshotContent.Name, err)
+		if isCSIFinalError(err) {
+			var removeAnnotationErr error
+			if groupSnapshotContent, removeAnnotationErr = ctrl.removeAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent); removeAnnotationErr != nil {
+				return groupSnapshotContent, fmt.Errorf("failed to remove VolumeGroupSnapshotBeingCreated annotation from the group snapshot content %s: %s", groupSnapshotContent.Name, removeAnnotationErr)
+			}
+		}
+
+		return groupSnapshotContent, fmt.Errorf("failed to take group snapshot of the volumes %s: %q", groupSnapshotContent.Spec.Source.PersistentVolumeNames, err)
+	}
+
+	klog.V(5).Infof("Created group snapshot: driver %s, groupSnapshotId %s, creationTime %v, readyToUse %t", driverName, groupSnapshotID, creationTime, readyToUse)
+
+	if creationTime.IsZero() {
+		creationTime = time.Now()
+	}
+
+	// Create individual snapshots and snapshot contents
+	var snapshotContentNames []string
+	for _, snapshot := range snapshots {
+		uuid, ok := uuidMap[snapshot.SourceVolumeId]
+		if !ok {
+			continue
+		}
+		volumeSnapshotContentName := GetSnapshotContentNameForVolumeGroupSnapshotContent(string(groupSnapshotContent.UID), uuid)
+		volumeSnapshotName := GetSnapshotNameForVolumeGroupSnapshotContent(string(groupSnapshotContent.UID), uuid)
+		volumeSnapshotNamespace := groupSnapshotContent.Spec.VolumeGroupSnapshotRef.Namespace
+		volumeSnapshotContent := &crdv1.VolumeSnapshotContent{
+			ObjectMeta: metav1.ObjectMeta{
+				Name: volumeSnapshotContentName,
+			},
+			Spec: crdv1.VolumeSnapshotContentSpec{
+				VolumeSnapshotRef: v1.ObjectReference{
+					Kind:      "VolumeSnapshots",
+					Name:      volumeSnapshotName,
+					Namespace: volumeSnapshotNamespace,
+				},
+				DeletionPolicy: groupSnapshotContent.Spec.DeletionPolicy,
+				Driver:         groupSnapshotContent.Spec.Driver,
+				Source: crdv1.VolumeSnapshotContentSource{
+					SnapshotHandle: &snapshot.SnapshotId,
+				},
+				// TODO: Populate this field when volume mode conversion is enabled by default
+				SourceVolumeMode: nil,
+			},
+			Status: &crdv1.VolumeSnapshotContentStatus{
+				VolumeGroupSnapshotContentName: &groupSnapshotContent.Name,
+			},
+		}
+		label := make(map[string]string)
+		label["volumeGroupSnapshotName"] = groupSnapshotContent.Spec.VolumeGroupSnapshotRef.Name
+		name := "f"
+		volumeSnapshot := &crdv1.VolumeSnapshot{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      volumeSnapshotName,
+				Namespace: volumeSnapshotNamespace,
+				Labels:    label,
+			},
+			Spec: crdv1.VolumeSnapshotSpec{
+				Source: crdv1.VolumeSnapshotSource{
+					VolumeSnapshotContentName: &volumeSnapshotContentName,
+				},
+			},
+		}
+		vsc, err := ctrl.clientset.SnapshotV1().VolumeSnapshotContents().Create(context.TODO(), volumeSnapshotContent, metav1.CreateOptions{})
+		if err != nil {
+			return groupSnapshotContent, err
+		}
+		snapshotContentNames = append(snapshotContentNames, vsc.Name)
+
+		klog.Infof("making snapshot %v %s %s", volumeSnapshot.Status, *volumeSnapshot.Status.VolumeGroupSnapshotName, name)
+		_, err = ctrl.clientset.SnapshotV1().VolumeSnapshots(volumeSnapshotNamespace).Create(context.TODO(), volumeSnapshot, metav1.CreateOptions{})
+		if err != nil {
+			return groupSnapshotContent, err
+		}
+		//		klog.Infof("raunak made snapshot 1 %v", spew.Sdump(sn))
+		//		sn.Status = &crdv1.VolumeSnapshotStatus{
+		//			VolumeGroupSnapshotName: &name,
+		//		}
+		//		sn, err = ctrl.clientset.SnapshotV1().VolumeSnapshots(volumeSnapshotNamespace).UpdateStatus(context.TODO(), sn, metav1.UpdateOptions{})
+		//		if err != nil {
+		//			klog.Infof("failed 2")
+		//			return groupSnapshotContent, err
+		//		}
+		//		klog.Infof("made snapshot 2 %v", spew.Sdump(sn))
+	}
+	klog.Infof("raunak 2")
+	newGroupSnapshotContent, err := ctrl.updateGroupSnapshotContentStatus(groupSnapshotContent, groupSnapshotID, readyToUse, creationTime.UnixNano(), snapshotContentNames)
+	if err != nil {
+		klog.Errorf("error updating status for volume group snapshot content %s: %v.", groupSnapshotContent.Name, err)
+		return groupSnapshotContent, fmt.Errorf("error updating status for volume group snapshot content %s: %v", groupSnapshotContent.Name, err)
+	}
+	groupSnapshotContent = newGroupSnapshotContent
+
+	// NOTE(xyang): handle create timeout
+	// Remove annotation to indicate storage system has successfully
+	// cut the group snapshot
+	groupSnapshotContent, err = ctrl.removeAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent)
+	if err != nil {
+		return groupSnapshotContent, fmt.Errorf("failed to remove VolumeGroupSnapshotBeingCreated annotation on the groupSnapshotContent %s: %q", groupSnapshotContent.Name, err)
+	}
+	return groupSnapshotContent, nil
+}
+
+func (ctrl *csiSnapshotSideCarController) getCSIGroupSnapshotInput(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotClass, map[string]string, error) {
+	className := groupSnapshotContent.Spec.VolumeGroupSnapshotClassName
+	klog.V(5).Infof("getCSIGroupSnapshotInput for group snapshot content [%s]", groupSnapshotContent.Name)
+	var class *crdv1alpha1.VolumeGroupSnapshotClass
+	var err error
+	if className != nil {
+		class, err = ctrl.getGroupSnapshotClass(*className)
+		if err != nil {
+			klog.Errorf("getCSISnapshotInput failed to getClassFromVolumeGroupSnapshot %s", err)
+			return nil, nil, err
+		}
+	} else {
+		// If dynamic provisioning, return failure if no group snapshot class
+		if len(groupSnapshotContent.Spec.Source.PersistentVolumeNames) != 0 {
+			klog.Errorf("failed to getCSISnapshotInput %s without a group snapshot class", groupSnapshotContent.Name)
+			return nil, nil, fmt.Errorf("failed to take group snapshot %s without a group snapshot class", groupSnapshotContent.Name)
+		}
+		// For pre-provisioned group snapshot, group snapshot class is not required
+		klog.V(5).Infof("getCSISnapshotInput for groupSnapshotContent [%s]: no VolumeGroupSnapshotClassName provided for pre-provisioned group snapshot", groupSnapshotContent.Name)
+	}
+
+	// TODO: Resolve snapshotting secret credentials.
+
+	return class, nil, nil
+}
+
+// getGroupSnapshotClass is a helper function to get group snapshot class from the class name.
+func (ctrl *csiSnapshotSideCarController) getGroupSnapshotClass(className string) (*crdv1alpha1.VolumeGroupSnapshotClass, error) {
+	klog.V(5).Infof("getGroupSnapshotClass: VolumeGroupSnapshotClassName [%s]", className)
+
+	class, err := ctrl.groupSnapshotClassLister.Get(className)
+	if err != nil {
+		klog.Errorf("failed to retrieve group snapshot class %s from the informer: %q", className, err)
+		return nil, err
+	}
+
+	return class, nil
+}
+
+// setAnnVolumeGroupSnapshotBeingCreated sets VolumeGroupSnapshotBeingCreated annotation
+// on VolumeGroupSnapshotContent
+// If set, it indicates group snapshot is being created
+func (ctrl *csiSnapshotSideCarController) setAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	if metav1.HasAnnotation(groupSnapshotContent.ObjectMeta, utils.AnnVolumeGroupSnapshotBeingCreated) {
+		// the annotation already exists, return directly
+		return groupSnapshotContent, nil
+	}
+
+	// Set AnnVolumeGroupSnapshotBeingCreated
+	// Combine existing annotations with the new annotations.
+	// If there are no existing annotations, we create a new map.
+	klog.V(5).Infof("setAnnVolumeGroupSnapshotBeingCreated: set annotation [%s:yes] on groupSnapshotContent [%s].", utils.AnnVolumeGroupSnapshotBeingCreated, groupSnapshotContent.Name)
+	patchedAnnotations := make(map[string]string)
+	for k, v := range groupSnapshotContent.GetAnnotations() {
+		patchedAnnotations[k] = v
+	}
+	patchedAnnotations[utils.AnnVolumeGroupSnapshotBeingCreated] = "yes"
+
+	var patches []utils.PatchOp
+	patches = append(patches, utils.PatchOp{
+		Op:    "replace",
+		Path:  "/metadata/annotations",
+		Value: patchedAnnotations,
+	})
+
+	patchedGroupSnapshotContent, err := utils.PatchVolumeGroupSnapshotContent(groupSnapshotContent, patches, ctrl.clientset)
+	if err != nil {
+		return groupSnapshotContent, newControllerUpdateError(groupSnapshotContent.Name, err.Error())
+	}
+	// update groupSnapshotContent if update is successful
+	groupSnapshotContent = patchedGroupSnapshotContent
+
+	_, err = ctrl.storeContentUpdate(groupSnapshotContent)
+	if err != nil {
+		klog.V(4).Infof("setAnnVolumeGroupSnapshotBeingCreated for groupSnapshotContent [%s]: cannot update internal cache %v", groupSnapshotContent.Name, err)
+	}
+	klog.V(5).Infof("setAnnVolumeGroupSnapshotBeingCreated: volume group snapshot content %+v", groupSnapshotContent)
+
+	return groupSnapshotContent, nil
+}
+
+func (ctrl *csiSnapshotSideCarController) getGroupSnapshotVolumeIDs(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) ([]string, map[string]string, error) {
+	// TODO: Get add PV lister
+	var volumeIDs []string
+	uuidMap := make(map[string]string)
+	for _, pvName := range groupSnapshotContent.Spec.Source.PersistentVolumeNames {
+		pv, err := ctrl.client.CoreV1().PersistentVolumes().Get(context.TODO(), pvName, metav1.GetOptions{})
+		if err != nil {
+			return nil, nil, err
+		}
+		if pv.Spec.CSI != nil && pv.Spec.CSI.VolumeHandle != "" {
+			volumeIDs = append(volumeIDs, pv.Spec.CSI.VolumeHandle)
+			if pv.Spec.ClaimRef != nil {
+				uuidMap[pv.Spec.CSI.VolumeHandle] = string(pv.Spec.ClaimRef.UID)
+			}
+		}
+	}
+	return volumeIDs, uuidMap, nil
+}
+
+// removeAnnVolumeGroupSnapshotBeingCreated removes the VolumeGroupSnapshotBeingCreated
+// annotation from a groupSnapshotContent if there exists one.
+func (ctrl csiSnapshotSideCarController) removeAnnVolumeGroupSnapshotBeingCreated(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	if !metav1.HasAnnotation(groupSnapshotContent.ObjectMeta, utils.AnnVolumeGroupSnapshotBeingCreated) {
+		// the annotation does not exist, return directly
+		return groupSnapshotContent, nil
+	}
+	groupSnapshotContentClone := groupSnapshotContent.DeepCopy()
+	delete(groupSnapshotContentClone.ObjectMeta.Annotations, utils.AnnVolumeGroupSnapshotBeingCreated)
+
+	updatedContent, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshotContents().Update(context.TODO(), groupSnapshotContentClone, metav1.UpdateOptions{})
+	if err != nil {
+		return groupSnapshotContent, newControllerUpdateError(groupSnapshotContent.Name, err.Error())
+	}
+
+	klog.V(5).Infof("Removed VolumeGroupSnapshotBeingCreated annotation from volume group snapshot content %s", groupSnapshotContent.Name)
+	_, err = ctrl.storeContentUpdate(updatedContent)
+	if err != nil {
+		klog.Errorf("failed to update groupSnapshotContent store %v", err)
+	}
+	return updatedContent, nil
+}
+
+func (ctrl *csiSnapshotSideCarController) updateGroupSnapshotContentStatus(
+	groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent,
+	groupSnapshotHandle string,
+	readyToUse bool,
+	createdAt int64,
+	snapshotContentNames []string) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	klog.V(5).Infof("updateSnapshotContentStatus: updating VolumeGroupSnapshotContent [%s], groupSnapshotHandle %s, readyToUse %v, createdAt %v", groupSnapshotContent.Name, groupSnapshotHandle, readyToUse, createdAt)
+
+	groupSnapshotContentObj, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshotContents().Get(context.TODO(), groupSnapshotContent.Name, metav1.GetOptions{})
+	if err != nil {
+		return nil, fmt.Errorf("error get group snapshot content %s from api server: %v", groupSnapshotContent.Name, err)
+	}
+
+	var newStatus *crdv1alpha1.VolumeGroupSnapshotContentStatus
+	updated := false
+	if groupSnapshotContentObj.Status == nil {
+		newStatus = &crdv1alpha1.VolumeGroupSnapshotContentStatus{
+			VolumeGroupSnapshotHandle: &groupSnapshotHandle,
+			ReadyToUse:                &readyToUse,
+			CreationTime:              &createdAt,
+		}
+		for _, name := range snapshotContentNames {
+			newStatus.VolumeSnapshotContentRefList = append(newStatus.VolumeSnapshotContentRefList, v1.ObjectReference{
+				Kind: "VolumeSnapshotContent",
+				Name: name,
+			})
+		}
+		updated = true
+	} else {
+		newStatus = groupSnapshotContentObj.Status.DeepCopy()
+		if newStatus.VolumeGroupSnapshotHandle == nil {
+			newStatus.VolumeGroupSnapshotHandle = &groupSnapshotHandle
+			updated = true
+		}
+		if newStatus.ReadyToUse == nil || *newStatus.ReadyToUse != readyToUse {
+			newStatus.ReadyToUse = &readyToUse
+			updated = true
+			if readyToUse && newStatus.Error != nil {
+				newStatus.Error = nil
+			}
+		}
+		if newStatus.CreationTime == nil {
+			newStatus.CreationTime = &createdAt
+			updated = true
+		}
+		if len(newStatus.VolumeSnapshotContentRefList) == 0 {
+			for _, name := range snapshotContentNames {
+				newStatus.VolumeSnapshotContentRefList = append(newStatus.VolumeSnapshotContentRefList, v1.ObjectReference{
+					Kind: "VolumeSnapshotContent",
+					Name: name,
+				})
+			}
+			updated = true
+		}
+	}
+
+	if updated {
+		groupSnapshotContentClone := groupSnapshotContentObj.DeepCopy()
+		groupSnapshotContentClone.Status = newStatus
+		newContent, err := ctrl.clientset.GroupsnapshotV1alpha1().VolumeGroupSnapshotContents().UpdateStatus(context.TODO(), groupSnapshotContentClone, metav1.UpdateOptions{})
+		if err != nil {
+			return groupSnapshotContentObj, newControllerUpdateError(groupSnapshotContent.Name, err.Error())
+		}
+		return newContent, nil
+	}
+
+	return groupSnapshotContentObj, nil
+}
+
+// updateContentStatusWithEvent saves new groupSnapshotContent.Status to API server
+// and emits given event on the groupSnapshotContent. It saves the status and emits
+// the event only when the status has actually changed from the version saved in API server.
+// Parameters:
+//
+// * groupSnapshotContent - group snapshot content to update
+// * eventtype, reason, message - event to send, see EventRecorder.Event()
+func (ctrl *csiSnapshotSideCarController) updateGroupSnapshotContentErrorStatusWithEvent(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent, eventtype, reason, message string) error {
+	klog.V(5).Infof("updateGroupSnapshotContentStatusWithEvent[%s]", groupSnapshotContent.Name)
+
+	if groupSnapshotContent.Status != nil && groupSnapshotContent.Status.Error != nil && *groupSnapshotContent.Status.Error.Message == message {
+		klog.V(4).Infof("updateGroupSnapshotContentStatusWithEvent[%s]: the same error %v is already set", groupSnapshotContent.Name, groupSnapshotContent.Status.Error)
+		return nil
+	}
+
+	var patches []utils.PatchOp
+	ready := false
+	groupSnapshotContentStatusError := &crdv1.VolumeSnapshotError{
+		Time: &metav1.Time{
+			Time: time.Now(),
+		},
+		Message: &message,
+	}
+	if groupSnapshotContent.Status == nil {
+		// Initialize status if nil
+		patches = append(patches, utils.PatchOp{
+			Op:   "replace",
+			Path: "/status",
+			Value: &crdv1alpha1.VolumeGroupSnapshotContentStatus{
+				ReadyToUse: &ready,
+				Error:      groupSnapshotContentStatusError,
+			},
+		})
+	} else {
+		// Patch status if non-nil
+		patches = append(patches, utils.PatchOp{
+			Op:    "replace",
+			Path:  "/status/error",
+			Value: groupSnapshotContentStatusError,
+		})
+		patches = append(patches, utils.PatchOp{
+			Op:    "replace",
+			Path:  "/status/readyToUse",
+			Value: &ready,
+		})
+
+	}
+
+	newContent, err := utils.PatchVolumeGroupSnapshotContent(groupSnapshotContent, patches, ctrl.clientset, "status")
+
+	// Emit the event even if the status update fails so that user can see the error
+	ctrl.eventRecorder.Event(newContent, eventtype, reason, message)
+
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshotContent[%s] error status failed %v", groupSnapshotContent.Name, err)
+		return err
+	}
+
+	_, err = ctrl.storeGroupSnapshotContentUpdate(newContent)
+	if err != nil {
+		klog.V(4).Infof("updating VolumeGroupSnapshotContent[%s] error status: cannot update internal cache %v", groupSnapshotContent.Name, err)
+		return err
+	}
+
+	return nil
+}
+
+// GetSnapshotNameForVolumeGroupSnapshotContent returns a unique snapshot name for a VolumeGroupSnapshotContent.
+func GetSnapshotNameForVolumeGroupSnapshotContent(groupSnapshotContentUUID, pvUUID string) string {
+	return fmt.Sprintf("snapshot-%x-%s", sha256.Sum256([]byte(groupSnapshotContentUUID+pvUUID)), time.Now().Format("2006-01-02-3.4.5"))
+}
+
+// GetSnapshotContentNameForVolumeGroupSnapshotContent returns a unique content name for the
+// passed in VolumeGroupSnapshotContent.
+func GetSnapshotContentNameForVolumeGroupSnapshotContent(groupSnapshotContentUUID, pvUUID string) string {
+	return fmt.Sprintf("snapcontent-%x-%s", sha256.Sum256([]byte(groupSnapshotContentUUID+pvUUID)), time.Now().Format("2006-01-02-3.4.5"))
+}
+
+func (ctrl *csiSnapshotSideCarController) checkandUpdateGroupSnapshotContentStatus(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) error {
+	klog.V(5).Infof("checkandUpdateGroupSnapshotContentStatus[%s] started", groupSnapshotContent.Name)
+	groupSnapshotContentObj, err := ctrl.checkandUpdateGroupSnapshotContentStatusOperation(groupSnapshotContent)
+	if err != nil {
+		ctrl.updateGroupSnapshotContentErrorStatusWithEvent(groupSnapshotContentObj, v1.EventTypeWarning, "GroupSnapshotContentCheckandUpdateFailed", fmt.Sprintf("Failed to check and update group snapshot content: %v", err))
+		klog.Errorf("checkandUpdateGroupSnapshotContentStatus [%s]: error occurred %v", groupSnapshotContent.Name, err)
+		return err
+	}
+	_, updateErr := ctrl.storeGroupSnapshotContentUpdate(groupSnapshotContentObj)
+	if updateErr != nil {
+		// We will get a "group snapshot update" event soon, this is not a big error
+		klog.V(4).Infof("checkandUpdateGroupSnapshotContentStatus [%s]: cannot update internal cache: %v", groupSnapshotContent.Name, updateErr)
+	}
+
+	return nil
+}
+
+func (ctrl *csiSnapshotSideCarController) checkandUpdateGroupSnapshotContentStatusOperation(groupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	var err error
+	var creationTime time.Time
+	readyToUse := false
+	var driverName string
+	var groupSnapshotID string
+	var snapshotterListCredentials map[string]string
+
+	if groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle != nil {
+		klog.V(5).Infof("checkandUpdateGroupSnapshotContentStatusOperation: call GetGroupSnapshotStatus for group snapshot which is pre-bound to group snapshot content [%s]", groupSnapshotContent.Name)
+
+		if groupSnapshotContent.Spec.VolumeGroupSnapshotClassName != nil {
+			class, err := ctrl.getGroupSnapshotClass(*groupSnapshotContent.Spec.VolumeGroupSnapshotClassName)
+			if err != nil {
+				klog.Errorf("Failed to get group snapshot class %s for group snapshot content %s: %v", *groupSnapshotContent.Spec.VolumeGroupSnapshotClassName, groupSnapshotContent.Name, err)
+				return groupSnapshotContent, fmt.Errorf("failed to get group snapshot class %s for group snapshot content %s: %v", *groupSnapshotContent.Spec.VolumeGroupSnapshotClassName, groupSnapshotContent.Name, err)
+			}
+
+			snapshotterListSecretRef, err := utils.GetSecretReference(utils.SnapshotterListSecretParams, class.Parameters, groupSnapshotContent.GetObjectMeta().GetName(), nil)
+			if err != nil {
+				klog.Errorf("Failed to get secret reference for group snapshot content %s: %v", groupSnapshotContent.Name, err)
+				return groupSnapshotContent, fmt.Errorf("failed to get secret reference for group snapshot content %s: %v", groupSnapshotContent.Name, err)
+			}
+
+			snapshotterListCredentials, err = utils.GetCredentials(ctrl.client, snapshotterListSecretRef)
+			if err != nil {
+				// Continue with deletion, as the secret may have already been deleted.
+				klog.Errorf("Failed to get credentials for group snapshot content %s: %v", groupSnapshotContent.Name, err)
+				return groupSnapshotContent, fmt.Errorf("failed to get credentials for group snapshot content %s: %v", groupSnapshotContent.Name, err)
+			}
+		}
+
+		readyToUse, creationTime, err = ctrl.handler.GetGroupSnapshotStatus(groupSnapshotContent, snapshotterListCredentials)
+		if err != nil {
+			klog.Errorf("checkandUpdateGroupSnapshotContentStatusOperation: failed to call get group snapshot status to check whether group snapshot is ready to use %q", err)
+			return groupSnapshotContent, err
+		}
+		driverName = groupSnapshotContent.Spec.Driver
+		groupSnapshotID = *groupSnapshotContent.Spec.Source.VolumeGroupSnapshotHandle
+
+		klog.V(5).Infof("checkandUpdateGroupSnapshotContentStatusOperation: driver %s, groupSnapshotId %s, creationTime %v, size %d, readyToUse %t", driverName, groupSnapshotID, creationTime, readyToUse)
+
+		if creationTime.IsZero() {
+			creationTime = time.Now()
+		}
+
+		// TODO: Get a reference to snapshot contents for this volume group snapshot
+		updatedContent, err := ctrl.updateGroupSnapshotContentStatus(groupSnapshotContent, groupSnapshotID, readyToUse, creationTime.UnixNano(), []string{})
+		if err != nil {
+			return groupSnapshotContent, err
+		}
+		return updatedContent, nil
+	}
+	return ctrl.createGroupSnapshotWrapper(groupSnapshotContent)
+}

pkg/sidecar-controller/snapshot_controller_base.go

@@ -18,15 +18,9 @@ package sidecar_controller
 
 import (
 	"fmt"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/group_snapshotter"
 	"time"
 
-	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
-	clientset "github.com/kubernetes-csi/external-snapshotter/client/v6/clientset/versioned"
-	storageinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumesnapshot/v1"
-	storagelisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumesnapshot/v1"
-	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/snapshotter"
-	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
-
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/labels"
@@ -38,6 +32,16 @@ import (
 	"k8s.io/client-go/tools/record"
 	"k8s.io/client-go/util/workqueue"
 	klog "k8s.io/klog/v2"
+
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
+	clientset "github.com/kubernetes-csi/external-snapshotter/client/v6/clientset/versioned"
+	groupsnapshotinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumegroupsnapshot/v1alpha1"
+	snapshotinformers "github.com/kubernetes-csi/external-snapshotter/client/v6/informers/externalversions/volumesnapshot/v1"
+	groupsnapshotlisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumegroupsnapshot/v1alpha1"
+	snapshotlisters "github.com/kubernetes-csi/external-snapshotter/client/v6/listers/volumesnapshot/v1"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/snapshotter"
+	"github.com/kubernetes-csi/external-snapshotter/v6/pkg/utils"
 )
 
 type csiSnapshotSideCarController struct {
@@ -48,9 +52,9 @@ type csiSnapshotSideCarController struct {
 	contentQueue        workqueue.RateLimitingInterface
 	extraCreateMetadata bool
 
-	contentLister       storagelisters.VolumeSnapshotContentLister
+	contentLister       snapshotlisters.VolumeSnapshotContentLister
 	contentListerSynced cache.InformerSynced
-	classLister         storagelisters.VolumeSnapshotClassLister
+	classLister         snapshotlisters.VolumeSnapshotClassLister
 	classListerSynced   cache.InformerSynced
 
 	contentStore cache.Store
@@ -58,6 +62,14 @@ type csiSnapshotSideCarController struct {
 	handler Handler
 
 	resyncPeriod time.Duration
+
+	enableVolumeGroupSnapshots       bool
+	groupSnapshotContentQueue        workqueue.RateLimitingInterface
+	groupSnapshotContentLister       groupsnapshotlisters.VolumeGroupSnapshotContentLister
+	groupSnapshotContentListerSynced cache.InformerSynced
+	groupSnapshotClassLister         groupsnapshotlisters.VolumeGroupSnapshotClassLister
+	groupSnapshotClassListerSynced   cache.InformerSynced
+	groupSnapshotContentStore        cache.Store
 }
 
 // NewCSISnapshotSideCarController returns a new *csiSnapshotSideCarController
@@ -65,15 +77,22 @@ func NewCSISnapshotSideCarController(
 	clientset clientset.Interface,
 	client kubernetes.Interface,
 	driverName string,
-	volumeSnapshotContentInformer storageinformers.VolumeSnapshotContentInformer,
-	volumeSnapshotClassInformer storageinformers.VolumeSnapshotClassInformer,
+	volumeSnapshotContentInformer snapshotinformers.VolumeSnapshotContentInformer,
+	volumeSnapshotClassInformer snapshotinformers.VolumeSnapshotClassInformer,
 	snapshotter snapshotter.Snapshotter,
+	groupSnapshotter group_snapshotter.GroupSnapshotter,
 	timeout time.Duration,
 	resyncPeriod time.Duration,
 	snapshotNamePrefix string,
 	snapshotNameUUIDLength int,
+	groupSnapshotNamePrefix string,
+	groupSnapshotNameUUIDLength int,
 	extraCreateMetadata bool,
 	contentRateLimiter workqueue.RateLimiter,
+	enableVolumeGroupSnapshots bool,
+	volumeGroupSnapshotContentInformer groupsnapshotinformers.VolumeGroupSnapshotContentInformer,
+	volumeGroupSnapshotClassInformer groupsnapshotinformers.VolumeGroupSnapshotClassInformer,
+	groupSnapshotContentRateLimiter workqueue.RateLimiter,
 ) *csiSnapshotSideCarController {
 	broadcaster := record.NewBroadcaster()
 	broadcaster.StartLogging(klog.Infof)
@@ -86,7 +105,7 @@ func NewCSISnapshotSideCarController(
 		client:              client,
 		driverName:          driverName,
 		eventRecorder:       eventRecorder,
-		handler:             NewCSIHandler(snapshotter, timeout, snapshotNamePrefix, snapshotNameUUIDLength),
+		handler:             NewCSIHandler(snapshotter, groupSnapshotter, timeout, snapshotNamePrefix, snapshotNameUUIDLength, groupSnapshotNamePrefix, groupSnapshotNameUUIDLength),
 		resyncPeriod:        resyncPeriod,
 		contentStore:        cache.NewStore(cache.DeletionHandlingMetaNamespaceKeyFunc),
 		contentQueue:        workqueue.NewNamedRateLimitingQueue(contentRateLimiter, "csi-snapshotter-content"),
@@ -124,6 +143,33 @@ func NewCSISnapshotSideCarController(
 	ctrl.classLister = volumeSnapshotClassInformer.Lister()
 	ctrl.classListerSynced = volumeSnapshotClassInformer.Informer().HasSynced
 
+	ctrl.enableVolumeGroupSnapshots = enableVolumeGroupSnapshots
+	if enableVolumeGroupSnapshots {
+		ctrl.groupSnapshotContentStore = cache.NewStore(cache.DeletionHandlingMetaNamespaceKeyFunc)
+		ctrl.groupSnapshotContentQueue = workqueue.NewNamedRateLimitingQueue(groupSnapshotContentRateLimiter, "csi-snapshotter-groupsnapshotcontent")
+
+		volumeGroupSnapshotContentInformer.Informer().AddEventHandlerWithResyncPeriod(
+			cache.ResourceEventHandlerFuncs{
+				AddFunc: func(obj interface{}) { ctrl.enqueueGroupSnapshotContentWork(obj) },
+				UpdateFunc: func(oldObj, newObj interface{}) {
+					/*
+						TODO: Determine if we need to skip requeueing in case of CSI driver failure.
+					*/
+					ctrl.enqueueGroupSnapshotContentWork(newObj)
+				},
+				DeleteFunc: func(obj interface{}) { ctrl.enqueueGroupSnapshotContentWork(obj) },
+			},
+			ctrl.resyncPeriod,
+		)
+
+		ctrl.groupSnapshotContentLister = volumeGroupSnapshotContentInformer.Lister()
+		ctrl.groupSnapshotContentListerSynced = volumeGroupSnapshotContentInformer.Informer().HasSynced
+
+		ctrl.groupSnapshotClassLister = volumeGroupSnapshotClassInformer.Lister()
+		ctrl.groupSnapshotClassListerSynced = volumeGroupSnapshotClassInformer.Informer().HasSynced
+
+	}
+
 	return ctrl
 }
 
@@ -133,15 +179,23 @@ func (ctrl *csiSnapshotSideCarController) Run(workers int, stopCh <-chan struct{
 	klog.Infof("Starting CSI snapshotter")
 	defer klog.Infof("Shutting CSI snapshotter")
 
-	if !cache.WaitForCacheSync(stopCh, ctrl.contentListerSynced, ctrl.classListerSynced) {
+	informersSynced := []cache.InformerSynced{ctrl.contentListerSynced, ctrl.classListerSynced}
+	if ctrl.enableVolumeGroupSnapshots {
+		informersSynced = append(informersSynced, []cache.InformerSynced{ctrl.groupSnapshotContentListerSynced, ctrl.groupSnapshotClassListerSynced}...)
+	}
+
+	if !cache.WaitForCacheSync(stopCh, informersSynced...) {
 		klog.Errorf("Cannot sync caches")
 		return
 	}
 
-	ctrl.initializeCaches(ctrl.contentLister)
+	ctrl.initializeCaches()
 
 	for i := 0; i < workers; i++ {
 		go wait.Until(ctrl.contentWorker, 0, stopCh)
+		if ctrl.enableVolumeGroupSnapshots {
+			go wait.Until(ctrl.groupSnapshotContentWorker, 0, stopCh)
+		}
 	}
 
 	<-stopCh
@@ -240,25 +294,48 @@ func (ctrl *csiSnapshotSideCarController) syncContentByKey(key string) error {
 	return nil
 }
 
-// verify whether the driver specified in VolumeSnapshotContent matches the controller's driver name
-func (ctrl *csiSnapshotSideCarController) isDriverMatch(content *crdv1.VolumeSnapshotContent) bool {
-	if content.Spec.Source.VolumeHandle == nil && content.Spec.Source.SnapshotHandle == nil {
-		// Skip this snapshot content if it does not have a valid source
-		return false
-	}
-	if content.Spec.Driver != ctrl.driverName {
-		// Skip this snapshot content if the driver does not match
-		return false
-	}
-	snapshotClassName := content.Spec.VolumeSnapshotClassName
-	if snapshotClassName != nil {
-		if snapshotClass, err := ctrl.classLister.Get(*snapshotClassName); err == nil {
-			if snapshotClass.Driver != ctrl.driverName {
-				return false
+// isDriverMatch verifies whether the driver specified in VolumeSnapshotContent
+// or VolumeGroupSnapshotContent matches the controller's driver name
+func (ctrl *csiSnapshotSideCarController) isDriverMatch(object interface{}) bool {
+	if content, ok := object.(*crdv1.VolumeSnapshotContent); ok {
+		if content.Spec.Source.VolumeHandle == nil && content.Spec.Source.SnapshotHandle == nil {
+			// Skip this snapshot content if it does not have a valid source
+			return false
+		}
+		if content.Spec.Driver != ctrl.driverName {
+			// Skip this snapshot content if the driver does not match
+			return false
+		}
+		snapshotClassName := content.Spec.VolumeSnapshotClassName
+		if snapshotClassName != nil {
+			if snapshotClass, err := ctrl.classLister.Get(*snapshotClassName); err == nil {
+				if snapshotClass.Driver != ctrl.driverName {
+					return false
+				}
 			}
 		}
+		return true
 	}
-	return true
+	if content, ok := object.(*crdv1alpha1.VolumeGroupSnapshotContent); ok {
+		if content.Spec.Source.VolumeGroupSnapshotHandle == nil && len(content.Spec.Source.PersistentVolumeNames) == 0 {
+			// Skip this group snapshot content if it does not have a valid source
+			return false
+		}
+		if content.Spec.Driver != ctrl.driverName {
+			// Skip this group snapshot content if the driver does not match
+			return false
+		}
+		groupSnapshotClassName := content.Spec.VolumeGroupSnapshotClassName
+		if groupSnapshotClassName != nil {
+			if groupSnapshotClass, err := ctrl.groupSnapshotClassLister.Get(*groupSnapshotClassName); err == nil {
+				if groupSnapshotClass.Driver != ctrl.driverName {
+					return false
+				}
+			}
+		}
+		return true
+	}
+	return false
 }
 
 // updateContentInInformerCache runs in worker thread and handles "content added",
@@ -296,8 +373,8 @@ func (ctrl *csiSnapshotSideCarController) deleteContentInCacheStore(content *crd
 // initializeCaches fills all controller caches with initial data from etcd in
 // order to have the caches already filled when first addSnapshot/addContent to
 // perform initial synchronization of the controller.
-func (ctrl *csiSnapshotSideCarController) initializeCaches(contentLister storagelisters.VolumeSnapshotContentLister) {
-	contentList, err := contentLister.List(labels.Everything())
+func (ctrl *csiSnapshotSideCarController) initializeCaches() {
+	contentList, err := ctrl.contentLister.List(labels.Everything())
 	if err != nil {
 		klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
 		return
@@ -311,5 +388,19 @@ func (ctrl *csiSnapshotSideCarController) initializeCaches(contentLister storage
 		}
 	}
 
+	if ctrl.enableVolumeGroupSnapshots {
+		groupSnapshotContentList, err := ctrl.groupSnapshotContentLister.List(labels.Everything())
+		if err != nil {
+			klog.Errorf("CSISnapshotController can't initialize caches: %v", err)
+			return
+		}
+		for _, groupSnapshotContent := range groupSnapshotContentList {
+			groupSnapshotContentClone := groupSnapshotContent.DeepCopy()
+			if _, err = ctrl.storeGroupSnapshotContentUpdate(groupSnapshotContentClone); err != nil {
+				klog.Errorf("error updating volume group snapshot content cache: %v", err)
+			}
+		}
+	}
+
 	klog.V(4).Infof("controller initialized")
 }

pkg/utils/patch.go

@@ -3,6 +3,7 @@ package utils
 import (
 	"context"
 	"encoding/json"
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
 
 	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
 	clientset "github.com/kubernetes-csi/external-snapshotter/client/v6/clientset/versioned"
@@ -56,3 +57,23 @@ func PatchVolumeSnapshot(
 
 	return newSnapshot, nil
 }
+
+// PatchVolumeGroupSnapshotContent patches a volume group snapshot content object
+func PatchVolumeGroupSnapshotContent(
+	existingGroupSnapshotContent *crdv1alpha1.VolumeGroupSnapshotContent,
+	patch []PatchOp,
+	client clientset.Interface,
+	subresources ...string,
+) (*crdv1alpha1.VolumeGroupSnapshotContent, error) {
+	data, err := json.Marshal(patch)
+	if nil != err {
+		return existingGroupSnapshotContent, err
+	}
+
+	newGroupSnapshotContent, err := client.GroupsnapshotV1alpha1().VolumeGroupSnapshotContents().Patch(context.TODO(), existingGroupSnapshotContent.Name, types.JSONPatchType, data, metav1.PatchOptions{}, subresources...)
+	if err != nil {
+		return existingGroupSnapshotContent, err
+	}
+
+	return newGroupSnapshotContent, nil
+}

pkg/utils/util.go

@@ -24,7 +24,6 @@ import (
 	"strings"
 	"time"
 
-	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -33,6 +32,9 @@ import (
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/cache"
 	klog "k8s.io/klog/v2"
+
+	crdv1alpha1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1"
+	crdv1 "github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumesnapshot/v1"
 )
 
 var keyFunc = cache.DeletionHandlingMetaNamespaceKeyFunc
@@ -62,6 +64,10 @@ const (
 	PrefixedVolumeSnapshotNamespaceKey   = csiParameterPrefix + "volumesnapshot/namespace"   // Prefixed VolumeSnapshot namespace key
 	PrefixedVolumeSnapshotContentNameKey = csiParameterPrefix + "volumesnapshotcontent/name" // Prefixed VolumeSnapshotContent name key
 
+	PrefixedVolumeGroupSnapshotNameKey        = csiParameterPrefix + "volumegroupsnapshot/name"        // Prefixed VolumeGroupSnapshot name key
+	PrefixedVolumeGroupSnapshotNamespaceKey   = csiParameterPrefix + "volumegroupsnapshot/namespace"   // Prefixed VolumeGroupSnapshot namespace key
+	PrefixedVolumeGroupSnapshotContentNameKey = csiParameterPrefix + "volumegroupsnapshotcontent/name" // Prefixed VolumeGroupSnapshotContent name key
+
 	// Name of finalizer on VolumeSnapshotContents that are bound by VolumeSnapshots
 	VolumeSnapshotContentFinalizer = "snapshot.storage.kubernetes.io/volumesnapshotcontent-bound-protection"
 	// Name of finalizer on VolumeSnapshot that is being used as a source to create a PVC
@@ -94,6 +100,19 @@ const (
 	// snapshots.
 	AnnVolumeSnapshotBeingCreated = "snapshot.storage.kubernetes.io/volumesnapshot-being-created"
 
+	// AnnVolumeGroupSnapshotBeingCreated annotation applies to VolumeGroupSnapshotContents.
+	// If it is set, it indicates that the csi-snapshotter
+	// sidecar has sent the create group snapshot request to the storage system and
+	// is waiting for a response of success or failure.
+	// This annotation will be removed once the driver's CreateGroupSnapshot
+	// CSI function returns success or a final error (determined by isFinalError()).
+	// If the create group snapshot request fails with a non-final error such as timeout,
+	// retry will happen and the annotation will remain.
+	// This only applies to dynamic provisioning of group snapshots because
+	// the create group snapshot CSI method will not be called for pre-provisioned
+	// group snapshots.
+	AnnVolumeGroupSnapshotBeingCreated = "groupsnapshot.storage.kubernetes.io/volumegroupsnapshot-being-created"
+
 	// Annotation for secret name and namespace will be added to the content
 	// and used at snapshot content deletion time.
 	AnnDeletionSecretRefName      = "snapshot.storage.kubernetes.io/deletion-secret-name"
@@ -475,3 +494,52 @@ func IsSnapshotReady(snapshot *crdv1.VolumeSnapshot) bool {
 func IsSnapshotCreated(snapshot *crdv1.VolumeSnapshot) bool {
 	return snapshot.Status != nil && snapshot.Status.CreationTime != nil
 }
+
+func GroupSnapshotKey(vgs *crdv1alpha1.VolumeGroupSnapshot) string {
+	return fmt.Sprintf("%s/%s", vgs.Namespace, vgs.Name)
+}
+
+func GroupSnapshotRefKey(vgsref *v1.ObjectReference) string {
+	return fmt.Sprintf("%s/%s", vgsref.Namespace, vgsref.Name)
+}
+
+func IsGroupSnapshotReady(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) bool {
+	if groupSnapshot.Status == nil || groupSnapshot.Status.ReadyToUse == nil || *groupSnapshot.Status.ReadyToUse == false {
+		return false
+	}
+	return true
+}
+
+func IsBoundVolumeGroupSnapshotContentNameSet(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) bool {
+	if groupSnapshot.Status == nil || groupSnapshot.Status.BoundVolumeGroupSnapshotContentName == nil || *groupSnapshot.Status.BoundVolumeGroupSnapshotContentName == "" {
+		return false
+	}
+	return true
+}
+
+func IsVolumeSnapshotRefListSet(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) bool {
+	if groupSnapshot.Status == nil || len(groupSnapshot.Status.VolumeSnapshotRefList) == 0 {
+		return false
+	}
+	return true
+}
+
+func IsVolumeGroupSnapshotRefSet(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot, content *crdv1alpha1.VolumeGroupSnapshotContent) bool {
+	if content.Spec.VolumeGroupSnapshotRef.Name == groupSnapshot.Name &&
+		content.Spec.VolumeGroupSnapshotRef.Namespace == groupSnapshot.Namespace &&
+		content.Spec.VolumeGroupSnapshotRef.UID == groupSnapshot.UID {
+		return true
+	}
+	return false
+}
+
+// IsGroupSnapshotCreated indicates that the group snapshot has been cut on a storage system
+func IsGroupSnapshotCreated(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) bool {
+	return groupSnapshot.Status != nil && groupSnapshot.Status.CreationTime != nil
+}
+
+// GetDynamicSnapshotContentNameFoGrouprSnapshot returns a unique content name for the
+// passed in VolumeGroupSnapshot to dynamically provision a group snapshot.
+func GetDynamicSnapshotContentNameForGroupSnapshot(groupSnapshot *crdv1alpha1.VolumeGroupSnapshot) string {
+	return "groupsnapcontent-" + string(groupSnapshot.UID)
+}

vendor/github.com/kubernetes-csi/external-snapshotter/client/v6/apis/volumegroupsnapshot/v1alpha1/types.go

@@ -326,7 +326,7 @@ type VolumeGroupSnapshotContentStatus struct {
 	// for this group snapshot.
 	// The maximum number of allowed snapshots in the group is 100.
 	// +optional
-	VolumeSnapshotContentRefList []core_v1.ObjectReference `json:"volumeSnapshotRefList,omitempty" protobuf:"bytes,5,opt,name=volumeSnapshotRefList"`
+	VolumeSnapshotContentRefList []core_v1.ObjectReference `json:"volumeSnapshotContentRefList,omitempty" protobuf:"bytes,5,opt,name=volumeSnapshotContentRefList"`
 }
 
 // VolumeGroupSnapshotContentSource represents the CSI source of a group snapshot.

vendor/modules.txt

@@ -7,7 +7,7 @@ github.com/blang/semver/v4
 # github.com/cespare/xxhash/v2 v2.1.2
 ## explicit; go 1.11
 github.com/cespare/xxhash/v2
-# github.com/container-storage-interface/spec v1.7.0
+# github.com/container-storage-interface/spec v1.8.0
 ## explicit; go 1.18
 github.com/container-storage-interface/spec/lib/go/csi
 # github.com/davecgh/go-spew v1.1.1