feedback: leasecandidate clients

Kubernetes-commit: fac758164029e278e9bda924090ed078bb6514c8

Author: Jefftree

tools/leaderelection/leaderelection.go

@@ -161,6 +161,7 @@ type LeaderElectionConfig struct {
 	Name string
 
 	// Coordinated will use the Coordinated Leader Election feature
+	// WARNING: Coordinated leader election is ALPHA.
 	Coordinated bool
 }
 
@@ -293,6 +294,7 @@ func (le *LeaderElector) renew(ctx context.Context) {
 			return
 		}
 		le.metrics.leaderOff(le.config.Name)
+		klog.Infof("failed to renew lease %v: %v", desc, err)
 		cancel()
 	}, le.config.RetryPeriod, ctx.Done())
 
@@ -354,23 +356,23 @@ func (le *LeaderElector) tryCoordinatedRenew(ctx context.Context) bool {
 
 		le.observedRawRecord = oldLeaderElectionRawRecord
 	}
-	hasExpired := le.observedTime.Add(time.Second * time.Duration(oldLeaderElectionRecord.LeaseDurationSeconds)).Before(now.Time)
 
+	hasExpired := le.observedTime.Add(time.Second * time.Duration(oldLeaderElectionRecord.LeaseDurationSeconds)).Before(now.Time)
 	if hasExpired {
 		klog.Infof("lock has expired: %v", le.config.Lock.Describe())
 		return false
 	}
 
 	if !le.IsLeader() {
-		klog.V(4).Infof("lock is held by %v and has not yet expired: %v", oldLeaderElectionRecord.HolderIdentity, le.config.Lock.Describe())
+		klog.V(6).Infof("lock is held by %v and has not yet expired: %v", oldLeaderElectionRecord.HolderIdentity, le.config.Lock.Describe())
 		return false
 	}
 
 	// 2b. If the lease has been marked as "end of term", don't renew it
 	if le.IsLeader() && oldLeaderElectionRecord.PreferredHolder != "" {
 		klog.V(4).Infof("lock is marked as 'end of term': %v", le.config.Lock.Describe())
 		// TODO: Instead of letting lease expire, the holder may deleted it directly
-		// This will not be compatible with all controllers, so it needs to be opt-in behavior..
+		// This will not be compatible with all controllers, so it needs to be opt-in behavior.
 		// We must ensure all code guarded by this lease has successfully completed
 		// prior to releasing or there may be two processes
 		// simultaneously acting on the critical path.

tools/leaderelection/leasecandidate.go

@@ -63,9 +63,14 @@ type LeaseCandidate struct {
 	preferredStrategies             []v1.CoordinatedLeaseStrategy
 }
 
+// NewCandidate creates new LeaseCandidate controller that creates a
+// LeaseCandidate object if it does not exist and watches changes
+// to the corresponding object and renews if PingTime is set.
+// WARNING: This is an ALPHA feature. Ensure that the CoordinatedLeaderElection
+// feature gate is on.
 func NewCandidate(clientset kubernetes.Interface,
-	candidateName string,
 	candidateNamespace string,
+	candidateName string,
 	targetLease string,
 	binaryVersion, emulationVersion string,
 	preferredStrategies []v1.CoordinatedLeaseStrategy,
@@ -144,7 +149,6 @@ func (c *LeaseCandidate) processNextWorkItem(ctx context.Context) bool {
 	}
 
 	utilruntime.HandleError(err)
-	klog.Infof("processNextWorkItem.AddRateLimited: %v", key)
 	c.queue.AddRateLimited(key)
 
 	return true
@@ -161,17 +165,16 @@ func (c *LeaseCandidate) ensureLease(ctx context.Context) error {
 	if apierrors.IsNotFound(err) {
 		klog.V(2).Infof("Creating lease candidate")
 		// lease does not exist, create it.
-		leaseToCreate := c.newLease()
-		_, err := c.leaseClient.Create(ctx, leaseToCreate, metav1.CreateOptions{})
-		if err != nil {
+		leaseToCreate := c.newLeaseCandidate()
+		if _, err := c.leaseClient.Create(ctx, leaseToCreate, metav1.CreateOptions{}); err != nil {
 			return err
 		}
 		klog.V(2).Infof("Created lease candidate")
 		return nil
 	} else if err != nil {
 		return err
 	}
-	klog.V(2).Infof("lease candidate exists.. renewing")
+	klog.V(2).Infof("lease candidate exists. Renewing.")
 	clone := lease.DeepCopy()
 	clone.Spec.RenewTime = &metav1.MicroTime{Time: c.clock.Now()}
 	clone.Spec.PingTime = nil
@@ -182,8 +185,8 @@ func (c *LeaseCandidate) ensureLease(ctx context.Context) error {
 	return nil
 }
 
-func (c *LeaseCandidate) newLease() *v1alpha1.LeaseCandidate {
-	lease := &v1alpha1.LeaseCandidate{
+func (c *LeaseCandidate) newLeaseCandidate() *v1alpha1.LeaseCandidate {
+	lc := &v1alpha1.LeaseCandidate{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      c.name,
 			Namespace: c.namespace,
@@ -195,6 +198,6 @@ func (c *LeaseCandidate) newLease() *v1alpha1.LeaseCandidate {
 			PreferredStrategies: c.preferredStrategies,
 		},
 	}
-	lease.Spec.RenewTime = &metav1.MicroTime{Time: c.clock.Now()}
-	return lease
+	lc.Spec.RenewTime = &metav1.MicroTime{Time: c.clock.Now()}
+	return lc
 }

tools/leaderelection/leasecandidate_test.go

@@ -48,8 +48,8 @@ func TestLeaseCandidateCreation(t *testing.T) {
 	client := fake.NewSimpleClientset()
 	candidate, _, err := NewCandidate(
 		client,
-		tc.candidateName,
 		tc.candidateNamespace,
+		tc.candidateName,
 		tc.leaseName,
 		tc.binaryVersion,
 		tc.emulationVersion,