[fix] Add regional PV support for GKE

fix #4663.
For GKE pv, when create backup, return all zones retrived from node affinity.

Signed-off-by: Xun Jiang <jxun@vmware.com>

changelogs/unreleased/4680-jxun

@@ -0,0 +1 @@
+Support regional pv for GKE

pkg/backup/item_backupper.go

@@ -21,6 +21,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/pkg/errors"
@@ -384,6 +385,7 @@ const (
 	awsEbsCsiZoneKey = "topology.ebs.csi.aws.com/zone"
 	azureCsiZoneKey  = "topology.disk.csi.azure.com/zone"
 	gkeCsiZoneKey    = "topology.gke.io/zone"
+	zoneSeparator    = "__"
 )
 
 // takePVSnapshot triggers a snapshot for the volume/disk underlying a PersistentVolume if the provided
@@ -539,15 +541,27 @@ func zoneFromPVNodeAffinity(res *corev1api.PersistentVolume, topologyKeys ...str
 		return "", ""
 	}
 	keySet := sets.NewString(topologyKeys...)
+	providerGke := false
+	zones := make([]string, 0)
 	for _, term := range nodeAffinity.Required.NodeSelectorTerms {
 		if term.MatchExpressions == nil {
 			continue
 		}
 		for _, exp := range term.MatchExpressions {
 			if keySet.Has(exp.Key) && exp.Operator == "In" && len(exp.Values) > 0 {
-				return exp.Key, exp.Values[0]
+				if exp.Key == gkeCsiZoneKey {
+					providerGke = true
+					zones = append(zones, exp.Values[0])
+				} else {
+					return exp.Key, exp.Values[0]
+				}
 			}
 		}
 	}
+
+	if providerGke {
+		return gkeCsiZoneKey, strings.Join(zones, zoneSeparator)
+	}
+
 	return "", ""
 }

pkg/backup/item_backupper_test.go

@@ -131,6 +131,21 @@ func Test_zoneFromPVNodeAffinity(t *testing.T) {
 			wantKey:   "topology.disk.csi.azure.com/zone",
 			wantValue: "us-central",
 		},
+		{
+			name: "Volume with multiple valid keys, and provider is gke, returns the all match", // it should never happen
+			pv: builder.ForPersistentVolume("multi-matching-pv").NodeAffinityRequired(
+				builder.ForNodeSelector(
+					*builder.NewNodeSelectorTermBuilder().WithMatchExpression("topology.gke.io/zone",
+						"In", "us-central1-c").Result(),
+					*builder.NewNodeSelectorTermBuilder().WithMatchExpression("topology.gke.io/zone",
+						"In", "us-east-2c", "us-east-2b").Result(),
+					*builder.NewNodeSelectorTermBuilder().WithMatchExpression("topology.gke.io/zone",
+						"In", "europe-north1-a").Result(),
+				).Result(),
+			).Result(),
+			wantKey:   "topology.gke.io/zone",
+			wantValue: "us-central1-c__us-east-2c__europe-north1-a",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {