Add the key for GKE zone for AZ collection

Signed-off-by: Daniel Jiang <jiangd@vmware.com>

changelogs/unreleased/4376-reasonerjt

@@ -0,0 +1 @@
+Add the key for GKE zone for AZ collection

pkg/backup/item_backupper.go

@@ -401,6 +401,7 @@ const (
 
 	awsEbsCsiZoneKey = "topology.ebs.csi.aws.com/zone"
 	azureCsiZoneKey  = "topology.disk.csi.azure.com/zone"
+	gkeCsiZoneKey    = "topology.gke.io/zone"
 )
 
 // takePVSnapshot triggers a snapshot for the volume/disk underlying a PersistentVolume if the provided
@@ -439,7 +440,7 @@ func (ib *itemBackupper) takePVSnapshot(obj runtime.Unstructured, log logrus.Fie
 		if !labelFound {
 			var k string
 			log.Infof("label %q is not present on PersistentVolume", zoneLabelDeprecated)
-			k, pvFailureDomainZone = zoneFromPVNodeAffinity(pv, awsEbsCsiZoneKey, azureCsiZoneKey, zoneLabel, zoneLabelDeprecated)
+			k, pvFailureDomainZone = zoneFromPVNodeAffinity(pv, awsEbsCsiZoneKey, azureCsiZoneKey, gkeCsiZoneKey, zoneLabel, zoneLabelDeprecated)
 			if pvFailureDomainZone != "" {
 				log.Infof("zone info from nodeAffinity requirements: %s, key: %s", pvFailureDomainZone, k)
 			} else {

pkg/backup/item_backupper_test.go

@@ -51,7 +51,9 @@ func Test_zoneFromPVNodeAffinity(t *testing.T) {
 	keys := []string{
 		awsEbsCsiZoneKey,
 		azureCsiZoneKey,
+		gkeCsiZoneKey,
 		zoneLabel,
+		zoneLabelDeprecated,
 	}
 	tests := []struct {
 		name      string
@@ -81,6 +83,17 @@ func Test_zoneFromPVNodeAffinity(t *testing.T) {
 			wantKey:   "topology.disk.csi.azure.com/zone",
 			wantValue: "us-central",
 		},
+		{
+			name: "GCP CSI Volume",
+			pv: builder.ForPersistentVolume("gcpcsi").NodeAffinityRequired(
+				builder.ForNodeSelector(
+					*builder.NewNodeSelectorTermBuilder().WithMatchExpression("topology.gke.io/zone",
+						"In", "us-west1-a").Result(),
+				).Result(),
+			).Result(),
+			wantKey:   "topology.gke.io/zone",
+			wantValue: "us-west1-a",
+		},
 		{
 			name: "AWS CSI Volume with multiple zone value, returns the first",
 			pv: builder.ForPersistentVolume("awscsi").NodeAffinityRequired(