From a9afaa1eee95e4b6f1b224372a52981c20573e48 Mon Sep 17 00:00:00 2001
From: Daniel Vega-Myhre <danielvm@google.com>
Date: Tue, 27 Jun 2023 18:06:09 +0000
Subject: [PATCH] add feature gate

---
 pkg/controller/job/job_controller.go      | 5 ++++-
 pkg/controller/job/job_controller_test.go | 5 ++++-
 pkg/features/kube_features.go             | 9 +++++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/pkg/controller/job/job_controller.go b/pkg/controller/job/job_controller.go
index cce20c08b5f..fa76c7ccff5 100644
--- a/pkg/controller/job/job_controller.go
+++ b/pkg/controller/job/job_controller.go
@@ -1482,7 +1482,10 @@ func (jm *Controller) manageJob(ctx context.Context, job *batch.Job, activePods
 					if completionIndex != unknownCompletionIndex {
 						template = podTemplate.DeepCopy()
 						addCompletionIndexAnnotation(template, completionIndex)
-						addCompletionIndexLabel(template, completionIndex)
+
+						if feature.DefaultFeatureGate.Enabled(features.PodIndexLabel) {
+							addCompletionIndexLabel(template, completionIndex)
+						}
 						template.Spec.Hostname = fmt.Sprintf("%s-%d", job.Name, completionIndex)
 						generateName = podGenerateNameWithIndex(job.Name, completionIndex)
 					}
diff --git a/pkg/controller/job/job_controller_test.go b/pkg/controller/job/job_controller_test.go
index 8087c16e8d2..a0608acbad3 100644
--- a/pkg/controller/job/job_controller_test.go
+++ b/pkg/controller/job/job_controller_test.go
@@ -962,7 +962,9 @@ func checkIndexedJobPods(t *testing.T, control *controller.FakePodControl, wantI
 	gotIndexes := sets.New[int]()
 	for _, p := range control.Templates {
 		checkJobCompletionEnvVariable(t, &p.Spec)
-		checkJobCompletionLabel(t, &p)
+		if feature.DefaultFeatureGate.Enabled(features.PodIndexLabel) {
+			checkJobCompletionLabel(t, &p)
+		}
 		ix := getCompletionIndex(p.Annotations)
 		if ix == -1 {
 			t.Errorf("Created pod %s didn't have completion index", p.Name)
@@ -4395,6 +4397,7 @@ func TestFinalizersRemovedExpectations(t *testing.T) {
 		t.Errorf("Timeout waiting for expectations (-want, +got):\n%s", diff)
 	}
 }
+
 func checkJobCompletionLabel(t *testing.T, p *v1.PodTemplateSpec) {
 	t.Helper()
 	labels := p.GetLabels()
diff --git a/pkg/features/kube_features.go b/pkg/features/kube_features.go
index 3827a55e388..26ea0409fe3 100644
--- a/pkg/features/kube_features.go
+++ b/pkg/features/kube_features.go
@@ -843,6 +843,13 @@ const (
 	//
 	// Enables In-Place Pod Vertical Scaling
 	InPlacePodVerticalScaling featuregate.Feature = "InPlacePodVerticalScaling"
+
+	// owner: @danielvegamyhre
+	// kep: https://kep.k8s.io/4017
+	// beta: v1.28
+	//
+	// Set pod completion index as a pod label for Indexed Jobs and StatefulSets.
+	PodIndexLabel featuregate.Feature = "PodIndexLabel"
 )
 
 func init() {
@@ -1072,6 +1079,8 @@ var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureS
 
 	InPlacePodVerticalScaling: {Default: false, PreRelease: featuregate.Alpha},
 
+	PodIndexLabel: {Default: true, PreRelease: featuregate.Beta},
+
 	// inherited features from generic apiserver, relisted here to get a conflict if it is changed
 	// unintentionally on either side: