Retry Pod/RC updates in kubectl rolling-update

kubernetes · Jun 21, 2016 · ee81e5e · ee81e5e
1 parent 62ce669
commit ee81e5e
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Showing 5 changed files with 168 additions and 113 deletions.
diff --git a/pkg/client/unversioned/conditions.go b/pkg/client/unversioned/conditions.go
@@ -18,7 +18,6 @@ package unversioned
 
 import (
 	"fmt"
-	"time"
 
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/errors"
@@ -29,61 +28,6 @@ import (
 	"k8s.io/kubernetes/pkg/watch"
 )
 
-// DefaultRetry is the recommended retry for a conflict where multiple clients
-// are making changes to the same resource.
-var DefaultRetry = wait.Backoff{
-	Steps:    5,
-	Duration: 10 * time.Millisecond,
-	Factor:   1.0,
-	Jitter:   0.1,
-}
-
-// DefaultBackoff is the recommended backoff for a conflict where a client
-// may be attempting to make an unrelated modification to a resource under
-// active management by one or more controllers.
-var DefaultBackoff = wait.Backoff{
-	Steps:    4,
-	Duration: 10 * time.Millisecond,
-	Factor:   5.0,
-	Jitter:   0.1,
-}
-
-// RetryConflict executes the provided function repeatedly, retrying if the server returns a conflicting
-// write. Callers should preserve previous executions if they wish to retry changes. It performs an
-// exponential backoff.
-//
-//     var pod *api.Pod
-//     err := RetryOnConflict(DefaultBackoff, func() (err error) {
-//       pod, err = c.Pods("mynamespace").UpdateStatus(podStatus)
-//       return
-//     })
-//     if err != nil {
-//       // may be conflict if max retries were hit
-//       return err
-//     }
-//     ...
-//
-// TODO: Make Backoff an interface?
-func RetryOnConflict(backoff wait.Backoff, fn func() error) error {
-	var lastConflictErr error
-	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
-		err := fn()
-		switch {
-		case err == nil:
-			return true, nil
-		case errors.IsConflict(err):
-			lastConflictErr = err
-			return false, nil
-		default:
-			return false, err
-		}
-	})
-	if err == wait.ErrWaitTimeout {
-		err = lastConflictErr
-	}
-	return err
-}
-
 // ControllerHasDesiredReplicas returns a condition that will be true if and only if
 // the desired replica count for a controller's ReplicaSelector equals the Replicas count.
 func ControllerHasDesiredReplicas(c Interface, controller *api.ReplicationController) wait.ConditionFunc {

diff --git a/pkg/client/unversioned/util.go b/pkg/client/unversioned/util.go
@@ -0,0 +1,79 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package unversioned
+
+import (
+	"time"
+
+	"k8s.io/kubernetes/pkg/api/errors"
+	"k8s.io/kubernetes/pkg/util/wait"
+)
+
+// DefaultRetry is the recommended retry for a conflict where multiple clients
+// are making changes to the same resource.
+var DefaultRetry = wait.Backoff{
+	Steps:    5,
+	Duration: 10 * time.Millisecond,
+	Factor:   1.0,
+	Jitter:   0.1,
+}
+
+// DefaultBackoff is the recommended backoff for a conflict where a client
+// may be attempting to make an unrelated modification to a resource under
+// active management by one or more controllers.
+var DefaultBackoff = wait.Backoff{
+	Steps:    4,
+	Duration: 10 * time.Millisecond,
+	Factor:   5.0,
+	Jitter:   0.1,
+}
+
+// RetryConflict executes the provided function repeatedly, retrying if the server returns a conflicting
+// write. Callers should preserve previous executions if they wish to retry changes. It performs an
+// exponential backoff.
+//
+//     var pod *api.Pod
+//     err := RetryOnConflict(DefaultBackoff, func() (err error) {
+//       pod, err = c.Pods("mynamespace").UpdateStatus(podStatus)
+//       return
+//     })
+//     if err != nil {
+//       // may be conflict if max retries were hit
+//       return err
+//     }
+//     ...
+//
+// TODO: Make Backoff an interface?
+func RetryOnConflict(backoff wait.Backoff, fn func() error) error {
+	var lastConflictErr error
+	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
+		err := fn()
+		switch {
+		case err == nil:
+			return true, nil
+		case errors.IsConflict(err):
+			lastConflictErr = err
+			return false, nil
+		default:
+			return false, err
+		}
+	})
+	if err == wait.ErrWaitTimeout {
+		err = lastConflictErr
+	}
+	return err
+}
diff --git a/pkg/client/unversioned/conditions_test.go → pkg/client/unversioned/util_test.go b/pkg/client/unversioned/conditions_test.go → pkg/client/unversioned/util_test.go
@@ -1,5 +1,5 @@
 /*
-Copyright 2014 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

diff --git a/pkg/kubectl/rolling_updater.go b/pkg/kubectl/rolling_updater.go
@@ -187,15 +187,16 @@ func (r *RollingUpdater) Update(config *RollingUpdaterConfig) error {
 		if err != nil {
 			return err
 		}
-		if existing.Annotations == nil {
-			existing.Annotations = map[string]string{}
+		originReplicas := strconv.Itoa(int(existing.Spec.Replicas))
+		applyUpdate := func(rc *api.ReplicationController) {
+			if rc.Annotations == nil {
+				rc.Annotations = map[string]string{}
+			}
+			rc.Annotations[originalReplicasAnnotation] = originReplicas
 		}
-		existing.Annotations[originalReplicasAnnotation] = strconv.Itoa(int(existing.Spec.Replicas))
-		updated, err := r.c.ReplicationControllers(existing.Namespace).Update(existing)
-		if err != nil {
+		if oldRc, err = updateRcWithRetries(r.c, existing.Namespace, existing, applyUpdate); err != nil {
 			return err
 		}
-		oldRc = updated
 	}
 	// maxSurge is the maximum scaling increment and maxUnavailable are the maximum pods
 	// that can be unavailable during a rollout.
@@ -482,13 +483,14 @@ func (r *RollingUpdater) cleanupWithClients(oldRc, newRc *api.ReplicationControl
 	if err != nil {
 		return err
 	}
-	delete(newRc.Annotations, sourceIdAnnotation)
-	delete(newRc.Annotations, desiredReplicasAnnotation)
-
-	newRc, err = r.c.ReplicationControllers(r.ns).Update(newRc)
-	if err != nil {
+	applyUpdate := func(rc *api.ReplicationController) {
+		delete(rc.Annotations, sourceIdAnnotation)
+		delete(rc.Annotations, desiredReplicasAnnotation)
+	}
+	if newRc, err = updateRcWithRetries(r.c, r.ns, newRc, applyUpdate); err != nil {
 		return err
 	}
+
 	if err = wait.Poll(config.Interval, config.Timeout, client.ControllerHasDesiredReplicas(r.c, newRc)); err != nil {
 		return err
 	}
@@ -643,27 +645,29 @@ func SetNextControllerAnnotation(rc *api.ReplicationController, name string) {
 }
 
 func UpdateExistingReplicationController(c client.Interface, oldRc *api.ReplicationController, namespace, newName, deploymentKey, deploymentValue string, out io.Writer) (*api.ReplicationController, error) {
-	SetNextControllerAnnotation(oldRc, newName)
 	if _, found := oldRc.Spec.Selector[deploymentKey]; !found {
+		SetNextControllerAnnotation(oldRc, newName)
 		return AddDeploymentKeyToReplicationController(oldRc, c, deploymentKey, deploymentValue, namespace, out)
 	} else {
 		// If we didn't need to update the controller for the deployment key, we still need to write
 		// the "next" controller.
-		return c.ReplicationControllers(namespace).Update(oldRc)
+		applyUpdate := func(rc *api.ReplicationController) {
+			SetNextControllerAnnotation(rc, newName)
+		}
+		return updateRcWithRetries(c, namespace, oldRc, applyUpdate)
 	}
 }
 
-const MaxRetries = 3
-
 func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, client client.Interface, deploymentKey, deploymentValue, namespace string, out io.Writer) (*api.ReplicationController, error) {
 	var err error
 	// First, update the template label.  This ensures that any newly created pods will have the new label
-	if oldRc, err = updateWithRetries(client.ReplicationControllers(namespace), oldRc, func(rc *api.ReplicationController) {
+	applyUpdate := func(rc *api.ReplicationController) {
 		if rc.Spec.Template.Labels == nil {
 			rc.Spec.Template.Labels = map[string]string{}
 		}
 		rc.Spec.Template.Labels[deploymentKey] = deploymentValue
-	}); err != nil {
+	}
+	if oldRc, err = updateRcWithRetries(client, namespace, oldRc, applyUpdate); err != nil {
 		return nil, err
 	}
 
@@ -677,26 +681,16 @@ func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, c
 	}
 	for ix := range podList.Items {
 		pod := &podList.Items[ix]
-		if pod.Labels == nil {
-			pod.Labels = map[string]string{
-				deploymentKey: deploymentValue,
-			}
-		} else {
-			pod.Labels[deploymentKey] = deploymentValue
-		}
-		err = nil
-		delay := 3
-		for i := 0; i < MaxRetries; i++ {
-			_, err = client.Pods(namespace).Update(pod)
-			if err != nil {
-				fmt.Fprintf(out, "Error updating pod (%v), retrying after %d seconds", err, delay)
-				time.Sleep(time.Second * time.Duration(delay))
-				delay *= delay
+		applyUpdate := func(p *api.Pod) {
+			if p.Labels == nil {
+				p.Labels = map[string]string{
+					deploymentKey: deploymentValue,
+				}
 			} else {
-				break
+				p.Labels[deploymentKey] = deploymentValue
 			}
 		}
-		if err != nil {
+		if pod, err = updatePodWithRetries(client, namespace, pod, applyUpdate); err != nil {
 			return nil, err
 		}
 	}
@@ -709,12 +703,11 @@ func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, c
 	for k, v := range oldRc.Spec.Selector {
 		selectorCopy[k] = v
 	}
-	oldRc.Spec.Selector[deploymentKey] = deploymentValue
-
-	// Update the selector of the rc so it manages all the pods we updated above
-	if oldRc, err = updateWithRetries(client.ReplicationControllers(namespace), oldRc, func(rc *api.ReplicationController) {
+	applyUpdate = func(rc *api.ReplicationController) {
 		rc.Spec.Selector[deploymentKey] = deploymentValue
-	}); err != nil {
+	}
+	// Update the selector of the rc so it manages all the pods we updated above
+	if oldRc, err = updateRcWithRetries(client, namespace, oldRc, applyUpdate); err != nil {
 		return nil, err
 	}
 
@@ -736,33 +729,72 @@ func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, c
 	return oldRc, nil
 }
 
-type updateFunc func(controller *api.ReplicationController)
+type updateRcFunc func(controller *api.ReplicationController)
 
-// updateWithRetries updates applies the given rc as an update.
-func updateWithRetries(rcClient client.ReplicationControllerInterface, rc *api.ReplicationController, applyUpdate updateFunc) (*api.ReplicationController, error) {
-	var err error
-	oldRc := rc
-	err = wait.Poll(10*time.Millisecond, 1*time.Minute, func() (bool, error) {
+// updateRcWithRetries retries updating the given rc on conflict with the following steps:
+// 1. Get latest resource
+// 2. applyUpdate
+// 3. Update the resource
+func updateRcWithRetries(c client.Interface, namespace string, rc *api.ReplicationController, applyUpdate updateRcFunc) (*api.ReplicationController, error) {
+	// Deep copy the rc in case we failed on Get during retry loop
+	obj, err := api.Scheme.Copy(rc)
+	if err != nil {
+		return nil, fmt.Errorf("failed to deep copy rc before updating it: %v", err)
+	}
+	oldRc := obj.(*api.ReplicationController)
+	err = client.RetryOnConflict(client.DefaultBackoff, func() (e error) {
 		// Apply the update, then attempt to push it to the apiserver.
 		applyUpdate(rc)
-		if rc, err = rcClient.Update(rc); err == nil {
+		if rc, e = c.ReplicationControllers(namespace).Update(rc); e == nil {
 			// rc contains the latest controller post update
-			return true, nil
+			return
 		}
+		updateErr := e
 		// Update the controller with the latest resource version, if the update failed we
 		// can't trust rc so use oldRc.Name.
-		if rc, err = rcClient.Get(oldRc.Name); err != nil {
+		if rc, e = c.ReplicationControllers(namespace).Get(oldRc.Name); e != nil {
 			// The Get failed: Value in rc cannot be trusted.
 			rc = oldRc
 		}
-		// The Get passed: rc contains the latest controller, expect a poll for the update.
-		return false, nil
+		// Only return the error from update
+		return updateErr
 	})
 	// If the error is non-nil the returned controller cannot be trusted, if it is nil, the returned
 	// controller contains the applied update.
 	return rc, err
 }
 
+type updatePodFunc func(controller *api.Pod)
+
+// updatePodWithRetries retries updating the given pod on conflict with the following steps:
+// 1. Get latest resource
+// 2. applyUpdate
+// 3. Update the resource
+func updatePodWithRetries(c client.Interface, namespace string, pod *api.Pod, applyUpdate updatePodFunc) (*api.Pod, error) {
+	// Deep copy the pod in case we failed on Get during retry loop
+	obj, err := api.Scheme.Copy(pod)
+	if err != nil {
+		return nil, fmt.Errorf("failed to deep copy pod before updating it: %v", err)
+	}
+	oldPod := obj.(*api.Pod)
+	err = client.RetryOnConflict(client.DefaultBackoff, func() (e error) {
+		// Apply the update, then attempt to push it to the apiserver.
+		applyUpdate(pod)
+		if pod, e = c.Pods(namespace).Update(pod); e == nil {
+			return
+		}
+		updateErr := e
+		if pod, e = c.Pods(namespace).Get(oldPod.Name); e != nil {
+			pod = oldPod
+		}
+		// Only return the error from update
+		return updateErr
+	})
+	// If the error is non-nil the returned pod cannot be trusted, if it is nil, the returned
+	// controller contains the applied update.
+	return pod, err
+}
+
 func FindSourceController(r client.ReplicationControllersNamespacer, namespace, name string) (*api.ReplicationController, error) {
 	list, err := r.ReplicationControllers(namespace).List(api.ListOptions{})
 	if err != nil {