Apply exponential backoff in servicecontroller before retrying

Issue #21952

pkg/controller/service/servicecontroller.go

@@ -44,13 +44,16 @@ const (
 	// How long to wait before retrying the processing of a service change.
 	// If this changes, the sleep in hack/jenkins/e2e.sh before downing a cluster
 	// should be changed appropriately.
-	processingRetryInterval = 5 * time.Second
+	minRetryDelay = 5 * time.Second
+	maxRetryDelay = 300 * time.Second
 
 	clientRetryCount    = 5
 	clientRetryInterval = 5 * time.Second
 
 	retryable    = true
 	notRetryable = false
+
+	doNotRetry = time.Duration(0)
 )
 
 type cachedService struct {
@@ -61,6 +64,9 @@ type cachedService struct {
 
 	// Ensures only one goroutine can operate on this service at any given time.
 	mu sync.Mutex
+
+	// Controls error back-off
+	lastRetryDelay time.Duration
 }
 
 type serviceCache struct {
@@ -184,21 +190,26 @@ func (s *ServiceController) watchServices(serviceQueue *cache.DeltaFIFO) {
 			glog.Errorf("Received nil delta from watcher queue.")
 			continue
 		}
-		err, shouldRetry := s.processDelta(delta)
+		err, retryDelay := s.processDelta(delta)
-		if shouldRetry {
+		if retryDelay != 0 {
 			// Add the failed service back to the queue so we'll retry it.
-			glog.Errorf("Failed to process service delta. Retrying: %v", err)
+			glog.Errorf("Failed to process service delta. Retrying in %s: %v", retryDelay, err)
-			time.Sleep(processingRetryInterval)
+			go func(deltas cache.Deltas, delay time.Duration) {
-			serviceQueue.AddIfNotPresent(deltas)
+				time.Sleep(delay)
+				if err := serviceQueue.AddIfNotPresent(deltas); err != nil {
+					glog.Errorf("Error requeuing service delta - will not retry: %v", err)
+				}
+			}(deltas, retryDelay)
 		} else if err != nil {
 			runtime.HandleError(fmt.Errorf("Failed to process service delta. Not retrying: %v", err))
 		}
 	}
 }
 
-// Returns an error if processing the delta failed, along with a boolean
+// Returns an error if processing the delta failed, along with a time.Duration
-// indicator of whether the processing should be retried.
+// indicating whether processing should be retried; zero means no-retry; otherwise
-func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
+// we should retry in that Duration.
+func (s *ServiceController) processDelta(delta *cache.Delta) (error, time.Duration) {
 	deltaService, ok := delta.Object.(*api.Service)
 	var namespacedName types.NamespacedName
 	var cachedService *cachedService
@@ -208,11 +219,11 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 		// cache for deleting.
 		key, ok := delta.Object.(cache.DeletedFinalStateUnknown)
 		if !ok {
-			return fmt.Errorf("Delta contained object that wasn't a service or a deleted key: %+v", delta), notRetryable
+			return fmt.Errorf("Delta contained object that wasn't a service or a deleted key: %+v", delta), doNotRetry
 		}
 		cachedService, ok = s.cache.get(key.Key)
 		if !ok {
-			return fmt.Errorf("Service %s not in cache even though the watcher thought it was. Ignoring the deletion.", key), notRetryable
+			return fmt.Errorf("Service %s not in cache even though the watcher thought it was. Ignoring the deletion.", key), doNotRetry
 		}
 		deltaService = cachedService.lastState
 		delta.Object = deltaService
@@ -236,7 +247,7 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 	service, err := s.kubeClient.Core().Services(namespacedName.Namespace).Get(namespacedName.Name)
 	if err != nil && !errors.IsNotFound(err) {
 		glog.Warningf("Failed to get most recent state of service %v from API (will retry): %v", namespacedName, err)
-		return err, retryable
+		return err, cachedService.nextRetryDelay()
 	} else if errors.IsNotFound(err) {
 		glog.V(2).Infof("Service %v not found, ensuring load balancer is deleted", namespacedName)
 		s.eventRecorder.Event(service, api.EventTypeNormal, "DeletingLoadBalancer", "Deleting load balancer")
@@ -244,11 +255,13 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 		if err != nil {
 			message := "Error deleting load balancer (will retry): " + err.Error()
 			s.eventRecorder.Event(deltaService, api.EventTypeWarning, "DeletingLoadBalancerFailed", message)
-			return err, retryable
+			return err, cachedService.nextRetryDelay()
 		}
 		s.eventRecorder.Event(deltaService, api.EventTypeNormal, "DeletedLoadBalancer", "Deleted load balancer")
 		s.cache.delete(namespacedName.String())
-		return nil, notRetryable
+
+		cachedService.resetRetryDelay()
+		return nil, doNotRetry
 	}
 
 	// Update the cached service (used above for populating synthetic deletes)
@@ -265,7 +278,7 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 		message += err.Error()
 		s.eventRecorder.Event(service, api.EventTypeWarning, "CreatingLoadBalancerFailed", message)
 
-		return err, retry
+		return err, cachedService.nextRetryDelay()
 	}
 	// Always update the cache upon success.
 	// NOTE: Since we update the cached service if and only if we successfully
@@ -274,7 +287,8 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 	cachedService.appliedState = service
 	s.cache.set(namespacedName.String(), cachedService)
 
-	return nil, notRetryable
+	cachedService.resetRetryDelay()
+	return nil, doNotRetry
 }
 
 // Returns whatever error occurred along with a boolean indicator of whether it
@@ -738,3 +752,21 @@ func wantsLoadBalancer(service *api.Service) bool {
 func loadBalancerIPsAreEqual(oldService, newService *api.Service) bool {
 	return oldService.Spec.LoadBalancerIP == newService.Spec.LoadBalancerIP
 }
+
+// Computes the next retry, using exponential backoff
+// mutex must be held.
+func (s *cachedService) nextRetryDelay() time.Duration {
+	s.lastRetryDelay = s.lastRetryDelay * 2
+	if s.lastRetryDelay < minRetryDelay {
+		s.lastRetryDelay = minRetryDelay
+	}
+	if s.lastRetryDelay > maxRetryDelay {
+		s.lastRetryDelay = maxRetryDelay
+	}
+	return s.lastRetryDelay
+}
+
+// Resets the retry exponential backoff.  mutex must be held.
+func (s *cachedService) resetRetryDelay() {
+	s.lastRetryDelay = time.Duration(0)
+}