feat: make leader election lease duration configurable

Signed-off-by: Dasmat13 <gptdasmat@gmail.com>

Author: Dasmat13

helm/aws-load-balancer-controller/README.md

@@ -250,6 +250,7 @@ The default values set by the application itself can be confirmed [here](https:/
 | `globalAcceleratorMaxConcurrentReconciles`                          | Maximum number of concurrently running reconcile loops for GlobalAccelerator objects                                                                                                                                                                                                                                                         | None                                              |
 | `globalAcceleratorMaxExponentialBackoffDelay`                       | Maximum duration of exponential backoff for GlobalAccelerator reconcile failures                                                                                                                                                                                                                                                             | None                                              |
 | `syncPeriod`                                                        | Period at which the controller forces the repopulation of its local object stores                                                                                                                                                                                                                                                            | None                                              |
+| `leaderElectionLeaseDuration`                                       | The duration that non-leader candidates will wait after observing a leadership renewal until attempting to acquire leadership of a led but unrenewed leader slot.                                                                                                                                                                           | None                                              |
 | `watchNamespace`                                                    | Namespace the controller watches for updates to Kubernetes objects, If empty, all namespaces are watched                                                                                                                                                                                                                                     | None                                              |
 | `disableIngressClassAnnotation`                                     | Disables the usage of kubernetes.io/ingress.class annotation                                                                                                                                                                                                                                                                                 | None                                              |
 | `disableIngressGroupNameAnnotation`                                 | Disables the usage of alb.ingress.kubernetes.io/group.name annotation                                                                                                                                                                                                                                                                        | None                                              |

helm/aws-load-balancer-controller/templates/deployment.yaml

@@ -139,6 +139,9 @@ spec:
         {{- if .Values.syncPeriod }}
         - --sync-period={{ .Values.syncPeriod }}
         {{- end }}
+        {{- if .Values.leaderElectionLeaseDuration }}
+        - --leader-election-lease-duration={{ .Values.leaderElectionLeaseDuration }}
+        {{- end }}
         {{- if .Values.watchNamespace }}
         - --watch-namespace={{ .Values.watchNamespace }}
         {{- end }}

helm/aws-load-balancer-controller/values.yaml

@@ -291,6 +291,9 @@ lbStabilizationMonitorInterval:
 # Period at which the controller forces the repopulation of its local object stores. (default 10h0m0s)
 syncPeriod:
 
+# The duration that non-leader candidates will wait after observing a leadership renewal until attempting to acquire leadership of a led but unrenewed leader slot.
+leaderElectionLeaseDuration:
+
 # Namespace the controller watches for updates to Kubernetes objects, If empty, all namespaces are watched.
 watchNamespace:
 

pkg/config/runtime_config.go

@@ -27,6 +27,7 @@ const (
 	flagEnableLeaderElection    = "enable-leader-election"
 	flagLeaderElectionID        = "leader-election-id"
 	flagLeaderElectionNamespace = "leader-election-namespace"
+	flagLeaderElectionLeaseDuration = "leader-election-lease-duration"
 	flagWatchNamespace          = "watch-namespace"
 	flagSyncPeriod              = "sync-period"
 	flagKubeconfig              = "kubeconfig"
@@ -64,6 +65,7 @@ type RuntimeConfig struct {
 	EnableLeaderElection    bool
 	LeaderElectionID        string
 	LeaderElectionNamespace string
+	LeaderElectionLeaseDuration time.Duration
 	WatchNamespace          string
 	SyncPeriod              time.Duration
 	WebhookCertDir          string
@@ -89,6 +91,8 @@ func (c *RuntimeConfig) BindFlags(fs *pflag.FlagSet) {
 		"Name of the leader election ID to use for this controller")
 	fs.StringVar(&c.LeaderElectionNamespace, flagLeaderElectionNamespace, defaultLeaderElectionNamespace,
 		"Name of the leader election ID to use for this controller")
+	fs.DurationVar(&c.LeaderElectionLeaseDuration, flagLeaderElectionLeaseDuration, 0,
+		"The duration that non-leader candidates will wait after observing a leadership renewal until attempting to acquire leadership of a led but unrenewed leader slot. This is effectively the maximum duration that a leader can be stopped before it is replaced by another candidate. This is only applicable if leader election is enabled.")
 	fs.StringVar(&c.WatchNamespace, flagWatchNamespace, defaultWatchNamespace,
 		"Namespace the controller watches for updates to Kubernetes objects, If empty, all namespaces are watched.")
 	fs.DurationVar(&c.SyncPeriod, flagSyncPeriod, defaultSyncPeriod,
@@ -181,6 +185,10 @@ func BuildRuntimeOptions(rtCfg RuntimeConfig, scheme *runtime.Scheme) (ctrl.Opti
 		}),
 	}
 
+	if rtCfg.LeaderElectionLeaseDuration > 0 {
+		opt.LeaseDuration = &rtCfg.LeaderElectionLeaseDuration
+	}
+
 	// cannot set DefaultNamespaces = corev1.NamespaceAll
 	// https://github.com/kubernetes-sigs/controller-runtime/issues/2628
 	if rtCfg.WatchNamespace != corev1.NamespaceAll {

pkg/config/runtime_config_test.go

@@ -0,0 +1,32 @@
+package config
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+func TestBuildRuntimeOptions_LeaderElectionLeaseDuration(t *testing.T) {
+	scheme := runtime.NewScheme()
+
+	t.Run("default lease duration (not set)", func(t *testing.T) {
+		cfg := RuntimeConfig{
+			LeaderElectionLeaseDuration: 0,
+		}
+		opts, err := BuildRuntimeOptions(cfg, scheme)
+		assert.NoError(t, err)
+		assert.Nil(t, opts.LeaseDuration)
+	})
+
+	t.Run("configured lease duration", func(t *testing.T) {
+		cfg := RuntimeConfig{
+			LeaderElectionLeaseDuration: 30 * time.Second,
+		}
+		opts, err := BuildRuntimeOptions(cfg, scheme)
+		assert.NoError(t, err)
+		assert.NotNil(t, opts.LeaseDuration)
+		assert.Equal(t, 30*time.Second, *opts.LeaseDuration)
+	})
+}