Address comments

pkg/util/deployment/deployment.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/apis/extensions"
 	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
+	unversionedcore "k8s.io/kubernetes/pkg/client/typed/generated/core/unversioned"
 	unversionedextensions "k8s.io/kubernetes/pkg/client/typed/generated/extensions/unversioned"
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/util/integer"
@@ -163,65 +164,50 @@ func rsAndPodsWithHashKeySynced(deployment extensions.Deployment, c clientset.In
 }
 
 // addHashKeyToRSAndPods adds pod-template-hash information to the given rs, if it's not already there, with the following steps:
-// 1. Add hash label to all pods this rs owns
-// 2. Add hash label to the rs's pod template, the rs's label, and the rs's selector
-// 3. Clean up all pods this rs owns but without the hash label (orphaned pods)
+// 1. Add hash label to the rs's pod template
+// 2. Add hash label to all pods this rs owns
+// 3. Add hash label to the rs's label and selector
+// 4. Add hash label to all pods this rs owns but without the hash label (orphaned pods)
 func addHashKeyToRSAndPods(deployment extensions.Deployment, c clientset.Interface, rs extensions.ReplicaSet, getPodList podListFunc) (*extensions.ReplicaSet, error) {
 	if labelsutil.SelectorHasLabel(rs.Spec.Selector, extensions.DefaultDeploymentUniqueLabelKey) {
 		return &rs, nil
 	}
 	namespace := deployment.Namespace
 	hash := fmt.Sprintf("%d", podutil.GetPodTemplateSpecHash(*rs.Spec.Template))
-	// 1. Update all pods managed by the rs to have the new hash label, so they will be correctly adopted.
-	selector, err := unversioned.LabelSelectorAsSelector(rs.Spec.Selector)
+	// 1. Add hash template label to the rs. This ensures that any newly created pods will have the new label.
+	updatedRS, err := updateRSWithRetries(c.Extensions().ReplicaSets(namespace), &rs, func(updated *extensions.ReplicaSet) {
+		updated.Spec.Template.Labels = labelsutil.AddLabel(updated.Spec.Template.Labels, extensions.DefaultDeploymentUniqueLabelKey, hash)
+	})
 	if err != nil {
 		return nil, err
 	}
-	options := api.ListOptions{LabelSelector: selector}
-	podList, err := getPodList(namespace, options)
+
+	// 2. Update all pods managed by the rs to have the new hash label, so they will be correctly adopted.
+	selector, err := unversioned.LabelSelectorAsSelector(rs.Spec.Selector)
 	if err != nil {
 		return nil, err
 	}
-	for _, pod := range podList.Items {
-		// If the pod already has the new hash label, avoid re-labeling it
-		if len(pod.Labels) > 0 && len(pod.Labels[extensions.DefaultDeploymentUniqueLabelKey]) > 0 {
-			continue
-		}
-		pod.Labels = labelsutil.AddLabel(pod.Labels, extensions.DefaultDeploymentUniqueLabelKey, hash)
-		delay, maxRetries := 3, 3
-		podName := pod.Name
-		for i := 0; i < maxRetries; i++ {
-			_, err = c.Core().Pods(namespace).Update(&pod)
-			if err == nil {
-				break
-			}
-			time.Sleep(time.Second * time.Duration(delay))
-			delay *= delay
-			getPod, err := c.Core().Pods(namespace).Get(podName)
+	options := api.ListOptions{LabelSelector: selector}
+	podList, err := getPodList(namespace, options)
 	if err != nil {
 		return nil, err
 	}
-			pod = *getPod
-		}
-		if err != nil {
+	if err = labelPodsWithHash(podList, c, namespace, hash); err != nil {
 		return nil, err
 	}
-	}
 
-	// 2. Update rs label, rs template label, and rs selector to include the new hash label
+	// 3. Update rs label, rs template label, and rs selector to include the new hash label
 	// Copy the old selector, so that we can scrub out any orphaned pods
 	oldSelector := rs.Spec.Selector
 	// Update the selector of the rs so it manages all the pods we updated above
-	updatedRS, err := updateRSWithRetries(c.Extensions().ReplicaSets(namespace), &rs, func(updated *extensions.ReplicaSet) {
+	if updatedRS, err = updateRSWithRetries(c.Extensions().ReplicaSets(namespace), &rs, func(updated *extensions.ReplicaSet) {
 		updated.Labels = labelsutil.AddLabel(updated.Labels, extensions.DefaultDeploymentUniqueLabelKey, hash)
-		updated.Spec.Template.Labels = labelsutil.AddLabel(updated.Spec.Template.Labels, extensions.DefaultDeploymentUniqueLabelKey, hash)
 		updated.Spec.Selector = labelsutil.AddLabelToSelector(updated.Spec.Selector, extensions.DefaultDeploymentUniqueLabelKey, hash)
-	})
-	if err != nil {
+	}); err != nil {
 		return nil, err
 	}
 
-	// 3. Clean up any orphaned pods that don't have the new label, this can happen if the rs manager
+	// 4. Label any orphaned pods that don't have the new label, this can happen if the rs manager
 	//    doesn't see the update to its pod template and creates a new pod with the old labels after
 	//    we've finished re-adopting existing pods to the rs.
 	selector, err = unversioned.LabelSelectorAsSelector(oldSelector)
@@ -230,20 +216,36 @@ func addHashKeyToRSAndPods(deployment extensions.Deployment, c clientset.Interfa
 	}
 	options = api.ListOptions{LabelSelector: selector}
 	podList, err = getPodList(namespace, options)
-	for _, pod := range podList.Items {
-		if value, found := pod.Labels[extensions.DefaultDeploymentUniqueLabelKey]; !found || value != hash {
-			if err := c.Core().Pods(namespace).Delete(pod.Name, nil); err != nil {
+	if err != nil {
 		return nil, err
 	}
-		}
+	if err = labelPodsWithHash(podList, c, namespace, hash); err != nil {
+		return nil, err
 	}
 
 	return updatedRS, nil
 }
 
-type updateFunc func(rs *extensions.ReplicaSet)
+// labelPodsWithHash labels all pods in the given podList with the new hash label.
+func labelPodsWithHash(podList *api.PodList, c clientset.Interface, namespace, hash string) error {
+	for _, pod := range podList.Items {
+		// Only label the pod that doesn't already have the new hash
+		if pod.Labels[extensions.DefaultDeploymentUniqueLabelKey] != hash {
+			if _, err := updatePodWithRetries(c.Core().Pods(namespace), &pod, func(updated *api.Pod) {
+				pod.Labels = labelsutil.AddLabel(pod.Labels, extensions.DefaultDeploymentUniqueLabelKey, hash)
+			}); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
 
-func updateRSWithRetries(rsClient unversionedextensions.ReplicaSetInterface, rs *extensions.ReplicaSet, applyUpdate updateFunc) (*extensions.ReplicaSet, error) {
+// TODO: use client library instead when it starts to support update retries
+//       see https://github.com/kubernetes/kubernetes/issues/21479
+type updateRSFunc func(rs *extensions.ReplicaSet)
+
+func updateRSWithRetries(rsClient unversionedextensions.ReplicaSetInterface, rs *extensions.ReplicaSet, applyUpdate updateRSFunc) (*extensions.ReplicaSet, error) {
 	var err error
 	oldRs := rs
 	err = wait.Poll(10*time.Millisecond, 1*time.Minute, func() (bool, error) {
@@ -267,6 +269,25 @@ func updateRSWithRetries(rsClient unversionedextensions.ReplicaSetInterface, rs
 	return rs, err
 }
 
+type updatePodFunc func(pod *api.Pod)
+
+func updatePodWithRetries(podClient unversionedcore.PodInterface, pod *api.Pod, applyUpdate updatePodFunc) (*api.Pod, error) {
+	var err error
+	oldPod := pod
+	err = wait.Poll(10*time.Millisecond, 1*time.Minute, func() (bool, error) {
+		// Apply the update, then attempt to push it to the apiserver.
+		applyUpdate(pod)
+		if pod, err = podClient.Update(pod); err == nil {
+			return true, nil
+		}
+		if pod, err = podClient.Get(oldPod.Name); err != nil {
+			pod = oldPod
+		}
+		return false, nil
+	})
+	return pod, err
+}
+
 // Returns the desired PodTemplateSpec for the new ReplicaSet corresponding to the given ReplicaSet.
 func GetNewReplicaSetTemplate(deployment extensions.Deployment) api.PodTemplateSpec {
 	// newRS will have the same template as in deployment spec, plus a unique label in some cases.