Add StatefulSet pod index as pod label (#119232)

* add statefulset pod index as pod label

* change statefulset pod index label name

* check 3 pods

* change label variable name

pkg/controller/statefulset/stateful_set_control_test.go

@@ -227,6 +227,31 @@ func CreatesPods(t *testing.T, set *apps.StatefulSet, invariants invariantFunc)
 	if set.Status.UpdatedReplicas != 3 {
 		t.Error("Failed to set UpdatedReplicas correctly")
 	}
+	// Check all pods have correct pod index label.
+	if utilfeature.DefaultFeatureGate.Enabled(features.PodIndexLabel) {
+		selector, err := metav1.LabelSelectorAsSelector(set.Spec.Selector)
+		if err != nil {
+			t.Error(err)
+		}
+		pods, err := om.podsLister.Pods(set.Namespace).List(selector)
+		if err != nil {
+			t.Error(err)
+		}
+		if len(pods) != 3 {
+			t.Errorf("Expected 3 pods, got %d", len(pods))
+		}
+		for _, pod := range pods {
+			podIndexFromLabel, exists := pod.Labels[apps.PodIndexLabel]
+			if !exists {
+				t.Errorf("Missing pod index label: %s", apps.PodIndexLabel)
+				continue
+			}
+			podIndexFromName := strconv.Itoa(getOrdinal(pod))
+			if podIndexFromLabel != podIndexFromName {
+				t.Errorf("Pod index label value (%s) does not match pod index in pod name (%s)", podIndexFromLabel, podIndexFromName)
+			}
+		}
+	}
 }
 
 func ScalesUp(t *testing.T, set *apps.StatefulSet, invariants invariantFunc) {

pkg/controller/statefulset/stateful_set_utils.go

@@ -390,12 +390,16 @@ func initIdentity(set *apps.StatefulSet, pod *v1.Pod) {
 // updateIdentity updates pod's name, hostname, and subdomain, and StatefulSetPodNameLabel to conform to set's name
 // and headless service.
 func updateIdentity(set *apps.StatefulSet, pod *v1.Pod) {
-	pod.Name = getPodName(set, getOrdinal(pod))
+	ordinal := getOrdinal(pod)
+	pod.Name = getPodName(set, ordinal)
 	pod.Namespace = set.Namespace
 	if pod.Labels == nil {
 		pod.Labels = make(map[string]string)
 	}
 	pod.Labels[apps.StatefulSetPodNameLabel] = pod.Name
+	if utilfeature.DefaultFeatureGate.Enabled(features.PodIndexLabel) {
+		pod.Labels[apps.PodIndexLabel] = strconv.Itoa(ordinal)
+	}
 }
 
 // isRunningAndReady returns true if pod is in the PodRunning Phase, if it has a condition of PodReady.

staging/src/k8s.io/api/apps/v1/types.go

@@ -17,7 +17,7 @@ limitations under the License.
 package v1
 
 import (
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	runtime "k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/intstr"
@@ -29,6 +29,7 @@ const (
 	DeprecatedRollbackTo           = "deprecated.deployment.rollback.to"
 	DeprecatedTemplateGeneration   = "deprecated.daemonset.template.generation"
 	StatefulSetPodNameLabel        = "statefulset.kubernetes.io/pod-name"
+	PodIndexLabel                  = "apps.kubernetes.io/pod-index"
 )
 
 // +genclient