fix bug where volume cloning topology requirements are ignored when chosing the location of the volume

Author: amacaskill

pkg/gce-pd-csi-driver/controller.go

@@ -36,6 +36,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/client-go/util/flowcontrol"
 	"k8s.io/klog/v2"
+	"k8s.io/utils/strings/slices"
 
 	"sigs.k8s.io/gcp-compute-persistent-disk-csi-driver/pkg/common"
 	gce "sigs.k8s.io/gcp-compute-persistent-disk-csi-driver/pkg/gce-cloud-provider/compute"
@@ -107,6 +108,14 @@ type workItem struct {
 	unpublishReq *csi.ControllerUnpublishVolumeRequest
 }
 
+// locationRequirements are additional location topology requirements that must be respected when creating a volume.
+type locationRequirements struct {
+	srcVolRegion         string
+	srcVolZone           string
+	srcReplicationType   string
+	cloneReplicationType string
+}
+
 var _ csi.ControllerServer = &GCEControllerServer{}
 
 const (
@@ -151,6 +160,44 @@ func isDiskReady(disk *gce.CloudDisk) (bool, error) {
 	return false, nil
 }
 
+// cloningLocationRequirements returns additional location requirements to be applied to the given create volume requests topology.
+// If the CreateVolumeRequest will use volume cloning, location requirements in compliance with the volume cloning limitations
+// will be returned: https://cloud.google.com/kubernetes-engine/docs/how-to/persistent-volumes/volume-cloning#limitations.
+func cloningLocationRequirements(req *csi.CreateVolumeRequest, cloneReplicationType string) (*locationRequirements, error) {
+	if !useVolumeCloning(req) {
+		return nil, nil
+	}
+	// If we are using volume cloning, this will be set.
+	volSrc := req.VolumeContentSource.GetVolume()
+	volSrcVolID := volSrc.GetVolumeId()
+
+	_, sourceVolKey, err := common.VolumeIDToKey(volSrcVolID)
+	if err != nil {
+		return nil, fmt.Errorf("volume ID is invalid: %w", err)
+	}
+
+	isZonalSrcVol := sourceVolKey.Type() == meta.Zonal
+	if isZonalSrcVol {
+		region, err := common.GetRegionFromZones([]string{sourceVolKey.Zone})
+		if err != nil {
+			return nil, fmt.Errorf("failed to get region from zones: %w", err)
+		}
+		sourceVolKey.Region = region
+	}
+
+	srcReplicationType := replicationTypeNone
+	if !isZonalSrcVol {
+		srcReplicationType = replicationTypeRegionalPD
+	}
+
+	return &locationRequirements{srcVolZone: sourceVolKey.Zone, srcVolRegion: sourceVolKey.Region, srcReplicationType: srcReplicationType, cloneReplicationType: cloneReplicationType}, nil
+}
+
+// useVolumeCloning returns true if the create volume request should be created with volume cloning.
+func useVolumeCloning(req *csi.CreateVolumeRequest) bool {
+	return req.VolumeContentSource != nil && req.VolumeContentSource.GetVolume() != nil
+}
+
 func (gceCS *GCEControllerServer) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest) (*csi.CreateVolumeResponse, error) {
 	var err error
 	// Validate arguments
@@ -186,12 +233,21 @@ func (gceCS *GCEControllerServer) CreateVolume(ctx context.Context, req *csi.Cre
 	if multiWriter {
 		gceAPIVersion = gce.GCEAPIVersionBeta
 	}
+
+	var locationTopReq *locationRequirements
+	if useVolumeCloning(req) {
+		locationTopReq, err = cloningLocationRequirements(req, params.ReplicationType)
+		if err != nil {
+			return nil, status.Errorf(codes.InvalidArgument, "failed to get location requirements: %v", err.Error())
+		}
+	}
+
 	// Determine the zone or zones+region of the disk
 	var zones []string
 	var volKey *meta.Key
 	switch params.ReplicationType {
 	case replicationTypeNone:
-		zones, err = pickZones(ctx, gceCS, req.GetAccessibilityRequirements(), 1)
+		zones, err = pickZones(ctx, gceCS, req.GetAccessibilityRequirements(), 1, locationTopReq)
 		if err != nil {
 			return nil, status.Errorf(codes.InvalidArgument, "CreateVolume failed to pick zones for disk: %v", err.Error())
 		}
@@ -201,7 +257,7 @@ func (gceCS *GCEControllerServer) CreateVolume(ctx context.Context, req *csi.Cre
 		volKey = meta.ZonalKey(name, zones[0])
 
 	case replicationTypeRegionalPD:
-		zones, err = pickZones(ctx, gceCS, req.GetAccessibilityRequirements(), 2)
+		zones, err = pickZones(ctx, gceCS, req.GetAccessibilityRequirements(), 2, locationTopReq)
 		if err != nil {
 			return nil, status.Errorf(codes.InvalidArgument, "CreateVolume failed to pick zones for disk: %v", err.Error())
 		}
@@ -1382,7 +1438,29 @@ func diskIsAttachedAndCompatible(deviceName string, instance *compute.Instance,
 	return false, nil
 }
 
-func pickZonesFromTopology(top *csi.TopologyRequirement, numZones int) ([]string, error) {
+// pickZonesInRegion will remove any zones that are not in the given region.
+func pickZonesInRegion(region string, zones []string) []string {
+	refinedZones := []string{}
+	for _, zone := range zones {
+		if strings.Contains(zone, region) {
+			refinedZones = append(refinedZones, zone)
+		}
+	}
+	return refinedZones
+}
+
+func prependZone(zone string, zones []string) []string {
+	newZones := []string{zone}
+	for i := 0; i < len(zones); i++ {
+		// Do not add a zone if it is equal to the zone that is already prepended to newZones.
+		if zones[i] != zone {
+			newZones = append(newZones, zones[i])
+		}
+	}
+	return newZones
+}
+
+func pickZonesFromTopology(top *csi.TopologyRequirement, numZones int, locationTopReq *locationRequirements) ([]string, error) {
 	reqZones, err := getZonesFromTopology(top.GetRequisite())
 	if err != nil {
 		return nil, fmt.Errorf("could not get zones from requisite topology: %w", err)
@@ -1392,6 +1470,39 @@ func pickZonesFromTopology(top *csi.TopologyRequirement, numZones int) ([]string
 		return nil, fmt.Errorf("could not get zones from preferred topology: %w", err)
 	}
 
+	if locationTopReq != nil {
+		srcVolZone := locationTopReq.srcVolZone
+		switch locationTopReq.cloneReplicationType {
+		// For zonal -> zonal cloning, the source disk zone must match the destination disk zone.
+		case replicationTypeNone:
+			// If the source volume zone is not in the topology requirement, we return an error.
+			if !slices.Contains(prefZones, srcVolZone) && !slices.Contains(reqZones, srcVolZone) {
+				volumeCloningReq := fmt.Sprintf("clone zone must match source disk zone: %s", srcVolZone)
+				return nil, fmt.Errorf("failed to find zone from topology %v: %s", top, volumeCloningReq)
+			}
+			return []string{srcVolZone}, nil
+		// For zonal or regional -> regional disk cloning, the source disk region must match the destination disk region.
+		case replicationTypeRegionalPD:
+			srcVolRegion := locationTopReq.srcVolRegion
+			prefZones = pickZonesInRegion(srcVolRegion, prefZones)
+			reqZones = pickZonesInRegion(srcVolRegion, reqZones)
+
+			if len(prefZones) == 0 && len(reqZones) == 0 {
+				volumeCloningReq := fmt.Sprintf("clone zone must reside in source disk region %s", srcVolRegion)
+				return nil, fmt.Errorf("failed to find zone from topology %v: %s", top, volumeCloningReq)
+			}
+
+			// For zonal -> regional disk cloning, one of the replicated zones must match the source zone.
+			if locationTopReq.srcReplicationType == replicationTypeNone {
+				if !slices.Contains(prefZones, srcVolZone) && !slices.Contains(reqZones, srcVolZone) {
+					volumeCloningReq := fmt.Sprintf("one of the replica zones of the clone must match the source disk zone: %s", srcVolZone)
+					return nil, fmt.Errorf("failed to find zone from topology %v: %s", top, volumeCloningReq)
+				}
+				prefZones = prependZone(srcVolZone, prefZones)
+			}
+		}
+	}
+
 	if numZones <= len(prefZones) {
 		return prefZones[0:numZones], nil
 	} else {
@@ -1450,16 +1561,25 @@ func getZoneFromSegment(seg map[string]string) (string, error) {
 	return zone, nil
 }
 
-func pickZones(ctx context.Context, gceCS *GCEControllerServer, top *csi.TopologyRequirement, numZones int) ([]string, error) {
+func pickZones(ctx context.Context, gceCS *GCEControllerServer, top *csi.TopologyRequirement, numZones int, locationTopReq *locationRequirements) ([]string, error) {
 	var zones []string
 	var err error
 	if top != nil {
-		zones, err = pickZonesFromTopology(top, numZones)
+		zones, err = pickZonesFromTopology(top, numZones, locationTopReq)
 		if err != nil {
 			return nil, fmt.Errorf("failed to pick zones from topology: %w", err)
 		}
 	} else {
-		zones, err = getDefaultZonesInRegion(ctx, gceCS, []string{gceCS.CloudProvider.GetDefaultZone()}, numZones)
+		existingZones := []string{gceCS.CloudProvider.GetDefaultZone()}
+		// We set existingZones to the source volume zone so that for zonal -> zonal cloning, the clone is provisioned
+		// in the same zone as the source volume, and for zonal -> regional, one of the replicated zones will always
+		// be the zone of the source volume. For regional -> regional cloning, the srcVolZone will not be set, so we
+		// just use the default zone.
+		if locationTopReq != nil && locationTopReq.srcReplicationType == replicationTypeNone {
+			existingZones = []string{locationTopReq.srcVolZone}
+		}
+		// If topology is nil, then the Immediate binding mode was used without setting allowedTopologies in the storageclass.
+		zones, err = getDefaultZonesInRegion(ctx, gceCS, existingZones, numZones)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get default %v zones in region: %w", numZones, err)
 		}