Merge pull request #52557 from enisoc/automated-cherry-pick-of-#51199…

…-upstream-release-1.6

Automatic merge from submit-queue.

Automated cherry pick of #51199

Cherry pick of #51199 on release-1.6.

This allows users to completely avoid any disruption due to #48327, by first upgrading to a 1.6.x release containing this patch, before upgrading to 1.7.x.

#51199: Makes Hostname and Subdomain fields of v1.PodSpec settable

pkg/api/validation/validation.go

@@ -2476,6 +2476,16 @@ func ValidatePodUpdate(newPod, oldPod *api.Pod) field.ErrorList {
 
 	// handle updateable fields by munging those fields prior to deep equal comparison.
 	mungedPod := *newPod
+
+	// allow hostname and subdomain to be updated if they are empty. This allows for migration between the beta
+	// annotations and the GA field when upgrading between Kubernetes 1.6.x and 1.7.x.
+	if oldPod.Spec.Hostname == "" {
+		mungedPod.Spec.Hostname = oldPod.Spec.Hostname
+	}
+	if oldPod.Spec.Subdomain == "" {
+		mungedPod.Spec.Subdomain = oldPod.Spec.Subdomain
+	}
+
 	// munge containers[*].image
 	var newContainers []api.Container
 	for ix, container := range mungedPod.Spec.Containers {

pkg/api/validation/validation_test.go

@@ -4836,6 +4836,54 @@ func TestValidatePodUpdate(t *testing.T) {
 			false,
 			"added invalid new toleration to existing tolerations in pod spec updates",
 		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Hostname: "bar"},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Hostname: ""},
+			},
+			true,
+			"update empty hostname",
+		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Subdomain: "bar"},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Subdomain: ""},
+			},
+			true,
+			"update empty subdomain",
+		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Hostname: "bar"},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Hostname: "baz"},
+			},
+			false,
+			"update hostname",
+		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Subdomain: "bar"},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Spec:       api.PodSpec{Subdomain: "baz"},
+			},
+			false,
+			"update subdomain",
+		},
 	}
 
 	for _, test := range tests {

pkg/controller/statefulset/stateful_set_control.go

@@ -139,6 +139,21 @@ func (ssc *defaultStatefulSetControl) UpdateStatefulSet(set *apps.StatefulSet, p
 				set.Name, replicas[i].Name)
 			return nil
 		}
+		// Enforce the StatefulSet invariants - we do this without respect to the Pod's readiness so that the endpoints
+		// controller can be notified of identity changes if a Pod becomes unready due to a DNS inconsistency with respect
+		// to the Pods identity.
+		if !identityMatches(set, replicas[i]) || !storageMatches(set, replicas[i]) {
+			// Make a deep copy so we don't mutate the shared cache
+			copy, err := api.Scheme.DeepCopy(replicas[i])
+			if err != nil {
+				return err
+			}
+			replica := copy.(*v1.Pod)
+			if err := ssc.podControl.UpdateStatefulPod(set, replica); err != nil {
+				return err
+			}
+		}
+
 		// If we have a Pod that has been created but is not running and ready we can not make progress.
 		// We must ensure that all for each Pod, when we create it, all of its predecessors, with respect to its
 		// ordinal, are Running and Ready.
@@ -147,19 +162,6 @@ func (ssc *defaultStatefulSetControl) UpdateStatefulSet(set *apps.StatefulSet, p
 				set.Name, replicas[i].Name)
 			return nil
 		}
-		// Enforce the StatefulSet invariants
-		if identityMatches(set, replicas[i]) && storageMatches(set, replicas[i]) {
-			continue
-		}
-		// Make a deep copy so we don't mutate the shared cache
-		copy, err := api.Scheme.DeepCopy(replicas[i])
-		if err != nil {
-			return err
-		}
-		replica := copy.(*v1.Pod)
-		if err := ssc.podControl.UpdateStatefulPod(set, replica); err != nil {
-			return err
-		}
 	}
 
 	// At this point, all of the current Replicas are Running and Ready, we can consider termination.

pkg/controller/statefulset/stateful_set_utils.go

@@ -207,6 +207,12 @@ func updateStorage(set *apps.StatefulSet, pod *v1.Pod) {
 func updateIdentity(set *apps.StatefulSet, pod *v1.Pod) {
 	pod.Name = getPodName(set, getOrdinal(pod))
 	pod.Namespace = set.Namespace
+	if pod.Spec.Hostname == "" {
+		pod.Spec.Hostname = pod.Name
+	}
+	if pod.Spec.Subdomain == "" {
+		pod.Spec.Subdomain = set.Spec.ServiceName
+	}
 	if pod.Annotations == nil {
 		pod.Annotations = make(map[string]string)
 	}

pkg/controller/statefulset/stateful_set_utils_test.go

@@ -139,6 +139,22 @@ func TestUpdateIdentity(t *testing.T) {
 	if !identityMatches(set, pod) {
 		t.Error("updateIdentity failed to update the Pods namespace")
 	}
+	pod.Spec.Hostname = ""
+	pod.Spec.Subdomain = ""
+	updateIdentity(set, pod)
+	if pod.Spec.Hostname != pod.Name || pod.Spec.Subdomain != set.Spec.ServiceName {
+		t.Errorf("want hostame=%s subdomain=%s got hostname=%s subdomain=%s",
+			pod.Name,
+			set.Spec.ServiceName,
+			pod.Spec.Hostname,
+			set.Spec.ServiceName)
+	}
+	pod.Spec.Hostname = "foo"
+	pod.Spec.Subdomain = "bar"
+	updateIdentity(set, pod)
+	if pod.Spec.Hostname != "foo" || pod.Spec.Subdomain != "bar" {
+		t.Errorf("want hostame=foo subdomain=bar got hostname=%s subdomain=%s", pod.Spec.Hostname, set.Spec.ServiceName)
+	}
 	pod = newStatefulSetPod(set, 1)
 	delete(pod.Annotations, podapi.PodHostnameAnnotation)
 	pod.Spec.Hostname = ""