fix disruption hot loop

pkg/controller/disruption/disruption.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/kubernetes/pkg/runtime"
 	"k8s.io/kubernetes/pkg/types"
 	"k8s.io/kubernetes/pkg/util/intstr"
+	utilruntime "k8s.io/kubernetes/pkg/util/runtime"
 	"k8s.io/kubernetes/pkg/util/wait"
 	"k8s.io/kubernetes/pkg/util/workqueue"
 	"k8s.io/kubernetes/pkg/watch"
@@ -64,7 +65,8 @@ type DisruptionController struct {
 	dController *cache.Controller
 	dLister     cache.StoreToDeploymentLister
 
-	queue *workqueue.Type
+	// PodDisruptionBudget keys that need to be synced.
+	queue workqueue.RateLimitingInterface
 
 	broadcaster record.EventBroadcaster
 	recorder    record.EventRecorder
@@ -87,7 +89,7 @@ func NewDisruptionController(podInformer cache.SharedIndexInformer, kubeClient *
 	dc := &DisruptionController{
 		kubeClient:    kubeClient,
 		podController: podInformer.GetController(),
-		queue:         workqueue.NewNamed("disruption"),
+		queue:         workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "disruption"),
 		broadcaster:   record.NewBroadcaster(),
 	}
 	dc.recorder = dc.broadcaster.NewRecorder(api.EventSource{Component: "controllermanager"})
@@ -390,33 +392,27 @@ func (dc *DisruptionController) getPodsForPdb(pdb *policy.PodDisruptionBudget) (
 }
 
 func (dc *DisruptionController) worker() {
-	work := func() bool {
-		key, quit := dc.queue.Get()
-		if quit {
-			return quit
-		}
-		defer dc.queue.Done(key)
-		glog.V(4).Infof("Syncing PodDisruptionBudget %q", key.(string))
-		if err := dc.sync(key.(string)); err != nil {
-			glog.Errorf("Error syncing PodDisruptionBudget %v, requeuing: %v", key.(string), err)
-			// TODO(mml): In order to be safe in the face of a total inability to write state
-			// changes, we should write an expiration timestamp here and consumers
-			// of the PDB state (the /evict subresource handler) should check that
-			// any 'true' state is relatively fresh.
-
-			// TODO(mml): file an issue to that effect
-
-			// TODO(mml): If we used a workqueue.RateLimitingInterface, we could
-			// improve our behavior (be a better citizen) when we need to retry.
-			dc.queue.Add(key)
-		}
+	for dc.processNextWorkItem() {
+	}
+}
+
+func (dc *DisruptionController) processNextWorkItem() bool {
+	dKey, quit := dc.queue.Get()
+	if quit {
 		return false
 	}
-	for {
-		if quit := work(); quit {
-			return
-		}
+	defer dc.queue.Done(dKey)
+
+	err := dc.sync(dKey.(string))
+	if err == nil {
+		dc.queue.Forget(dKey)
+		return true
 	}
+
+	utilruntime.HandleError(fmt.Errorf("Error syncing PodDisruptionBudget %v, requeuing: %v", dKey.(string), err))
+	dc.queue.AddRateLimited(dKey)
+
+	return true
 }
 
 func (dc *DisruptionController) sync(key string) error {
@@ -427,10 +423,10 @@ func (dc *DisruptionController) sync(key string) error {
 
 	obj, exists, err := dc.pdbLister.Store.GetByKey(key)
 	if !exists {
-		return err
+		glog.V(4).Infof("PodDisruptionBudget %q has been deleted", key)
+		return nil
 	}
 	if err != nil {
-		glog.Errorf("unable to retrieve PodDisruptionBudget %v from store: %v", key, err)
 		return err
 	}
 

pkg/controller/disruption/disruption_test.go

@@ -490,3 +490,13 @@ func TestTwoControllers(t *testing.T) {
 	dc.sync(pdbName)
 	ps.VerifyPdbStatus(t, pdbName, true, 7, 7, 22)
 }
+
+// Test pdb doesn't exist
+func TestPDBNotExist(t *testing.T) {
+	dc, _ := newFakeDisruptionController()
+	pdb, _ := newPodDisruptionBudget(t, intstr.FromString("67%"))
+	add(t, dc.pdbLister.Store, pdb)
+	if err := dc.sync("notExist"); err != nil {
+		t.Errorf("Unexpected error: %v, expect nil", err)
+	}
+}