Merge pull request kubernetes-sigs#1773 from joelanford/feat/leader-election-use-leases-only

⚠ leaderelection: use 'leases' as default resource lock object

Author: k8s-ci-robot

pkg/leaderelection/leader_election.go

@@ -27,6 +27,7 @@ import (
 	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
+
 	"sigs.k8s.io/controller-runtime/pkg/recorder"
 )
 
@@ -39,7 +40,7 @@ type Options struct {
 	LeaderElection bool
 
 	// LeaderElectionResourceLock determines which resource lock to use for leader election,
-	// defaults to "configmapsleases".
+	// defaults to "leases".
 	LeaderElectionResourceLock string
 
 	// LeaderElectionNamespace determines the namespace in which the leader
@@ -57,11 +58,12 @@ func NewResourceLock(config *rest.Config, recorderProvider recorder.Provider, op
 		return nil, nil
 	}
 
-	// Default resource lock to "configmapsleases". We must keep this default until we are sure all controller-runtime
-	// users have upgraded from the original default ConfigMap lock to a controller-runtime version that has this new
-	// default. Many users of controller-runtime skip versions, so we should be extremely conservative here.
+	// Default resource lock to "leases". The previous default (from v0.7.0 to v0.11.x) was configmapsleases, which was
+	// used to migrate from configmaps to leases. Since the default was "configmapsleases" for over a year, spanning
+	// five minor releases, any actively maintained operators are very likely to have a released version that uses
+	// "configmapsleases". Therefore defaulting to "leases" should be safe.
 	if options.LeaderElectionResourceLock == "" {
-		options.LeaderElectionResourceLock = resourcelock.ConfigMapsLeasesResourceLock
+		options.LeaderElectionResourceLock = resourcelock.LeasesResourceLock
 	}
 
 	// LeaderElectionID must be provided to prevent clashes

pkg/manager/manager_test.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
 	configv1alpha1 "k8s.io/component-base/config/v1alpha1"
+
 	"sigs.k8s.io/controller-runtime/pkg/cache"
 	"sigs.k8s.io/controller-runtime/pkg/cache/informertest"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -446,33 +447,33 @@ var _ = Describe("manger.Manager", func() {
 			// We must keep this default until we are sure all controller-runtime users have upgraded from the original default
 			// ConfigMap lock to a controller-runtime version that has this new default. Many users of controller-runtime skip
 			// versions, so we should be extremely conservative here.
-			It("should default to ConfigMapsLeasesResourceLock", func() {
+			It("should default to LeasesResourceLock", func() {
 				m, err := New(cfg, Options{LeaderElection: true, LeaderElectionID: "controller-runtime", LeaderElectionNamespace: "my-ns"})
 				Expect(m).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				cm, ok := m.(*controllerManager)
 				Expect(ok).To(BeTrue())
-				multilock, isMultiLock := cm.resourceLock.(*resourcelock.MultiLock)
-				Expect(isMultiLock).To(BeTrue())
-				_, primaryIsConfigMapLock := multilock.Primary.(*resourcelock.ConfigMapLock)
-				Expect(primaryIsConfigMapLock).To(BeTrue())
-				_, secondaryIsLeaseLock := multilock.Secondary.(*resourcelock.LeaseLock)
-				Expect(secondaryIsLeaseLock).To(BeTrue())
+				_, isLeaseLock := cm.resourceLock.(*resourcelock.LeaseLock)
+				Expect(isLeaseLock).To(BeTrue())
 
 			})
 			It("should use the specified ResourceLock", func() {
 				m, err := New(cfg, Options{
 					LeaderElection:             true,
-					LeaderElectionResourceLock: resourcelock.LeasesResourceLock,
+					LeaderElectionResourceLock: resourcelock.ConfigMapsLeasesResourceLock,
 					LeaderElectionID:           "controller-runtime",
 					LeaderElectionNamespace:    "my-ns",
 				})
 				Expect(m).ToNot(BeNil())
 				Expect(err).ToNot(HaveOccurred())
 				cm, ok := m.(*controllerManager)
 				Expect(ok).To(BeTrue())
-				_, isLeaseLock := cm.resourceLock.(*resourcelock.LeaseLock)
-				Expect(isLeaseLock).To(BeTrue())
+				multilock, isMultiLock := cm.resourceLock.(*resourcelock.MultiLock)
+				Expect(isMultiLock).To(BeTrue())
+				_, primaryIsConfigMapLock := multilock.Primary.(*resourcelock.ConfigMapLock)
+				Expect(primaryIsConfigMapLock).To(BeTrue())
+				_, secondaryIsLeaseLock := multilock.Secondary.(*resourcelock.LeaseLock)
+				Expect(secondaryIsLeaseLock).To(BeTrue())
 			})
 			It("should release lease if ElectionReleaseOnCancel is true", func() {
 				var rl resourcelock.Interface