Add options to customize leader election (#257)

* Add options to customize leader election

Author: shyamradhakrishnan

cloud/scope/load_balancer_reconciler.go

@@ -273,12 +273,12 @@ func (s *ClusterScope) GetLoadBalancers(ctx context.Context) (*loadbalancer.Load
 			return nil, errors.New("cluster api tags have been modified out of context")
 		}
 	}
-	var page *string;
+	var page *string
 	for {
 		lbs, err := s.LoadBalancerClient.ListLoadBalancers(ctx, loadbalancer.ListLoadBalancersRequest{
 			CompartmentId: common.String(s.GetCompartmentId()),
 			DisplayName:   common.String(s.GetControlPlaneLoadBalancerName()),
-			Page: page,
+			Page:          page,
 		})
 		if err != nil {
 			s.Logger.Error(err, "Failed to list lb by name")

cloud/scope/machine.go

@@ -323,8 +323,8 @@ func (m *MachineScope) getMachineFromOCID(ctx context.Context, instanceID *strin
 // GetMachineByDisplayName returns the machine from the compartment if there is a matching DisplayName,
 // and it was created by the cluster
 func (m *MachineScope) GetMachineByDisplayName(ctx context.Context, name string) (*core.Instance, error) {
-	var page *string;
-	for  {
+	var page *string
+	for {
 		req := core.ListInstancesRequest{DisplayName: common.String(name),
 			CompartmentId: common.String(m.getCompartmentId()), Page: page}
 		resp, err := m.ComputeClient.ListInstances(ctx, req)

main.go

@@ -19,6 +19,7 @@ package main
 import (
 	"flag"
 	"os"
+	"time"
 
 	infrastructurev1beta1 "github.com/oracle/cluster-api-provider-oci/api/v1beta1"
 	infrastructurev1beta2 "github.com/oracle/cluster-api-provider-oci/api/v1beta2"
@@ -35,6 +36,7 @@ import (
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
+	"k8s.io/client-go/tools/leaderelection/resourcelock"
 	"k8s.io/component-base/logs"
 	logsV1 "k8s.io/component-base/logs/api/v1"
 	_ "k8s.io/component-base/logs/json/register"
@@ -79,6 +81,11 @@ func init() {
 func main() {
 	var metricsAddr string
 	var enableLeaderElection bool
+	var leaderElectionNamespace string
+	var leaderElectionLeaseDuration time.Duration
+	var leaderElectionRenewDeadline time.Duration
+	var leaderElectionRetryPeriod time.Duration
+	var watchNamespace string
 	var probeAddr string
 	var webhookPort int
 
@@ -91,6 +98,30 @@ func main() {
 	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
+	flag.StringVar(
+		&leaderElectionNamespace,
+		"leader-election-namespace",
+		"",
+		"Namespace that the controller performs leader election in. If unspecified, the controller will discover which namespace it is running in.",
+	)
+	flag.DurationVar(
+		&leaderElectionLeaseDuration,
+		"leader-elect-lease-duration",
+		15*time.Second,
+		"Interval at which non-leader candidates will wait to force acquire leadership (duration string)",
+	)
+	flag.DurationVar(
+		&leaderElectionRenewDeadline,
+		"leader-elect-renew-deadline",
+		10*time.Second,
+		"Duration that the leading controller manager will retry refreshing leadership before giving up (duration string)",
+	)
+	flag.DurationVar(
+		&leaderElectionRetryPeriod,
+		"leader-elect-retry-period",
+		2*time.Second,
+		"Duration the LeaderElector clients should wait between tries of actions (duration string)",
+	)
 	flag.IntVar(&webhookPort,
 		"webhook-port",
 		9443,
@@ -122,6 +153,12 @@ func main() {
 		true,
 		"Initialize OCI clients on startup",
 	)
+	flag.StringVar(
+		&watchNamespace,
+		"namespace",
+		"",
+		"Namespace that the controller watches to reconcile cluster-api objects. If unspecified, the controller watches for cluster-api objects across all namespaces.",
+	)
 
 	opts := zap.Options{
 		Development: true,
@@ -142,13 +179,19 @@ func main() {
 	ctrl.SetLogger(klog.Background())
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
-		Scheme:                 scheme,
-		MetricsBindAddress:     metricsAddr,
-		Port:                   webhookPort,
-		HealthProbeBindAddress: probeAddr,
-		LeaderElection:         enableLeaderElection,
-		LeaderElectionID:       "controller-leader-elect-capoci",
-		CertDir:                webhookCertDir,
+		Scheme:                     scheme,
+		MetricsBindAddress:         metricsAddr,
+		Port:                       webhookPort,
+		HealthProbeBindAddress:     probeAddr,
+		LeaderElection:             enableLeaderElection,
+		LeaderElectionID:           "controller-leader-elect-capoci",
+		LeaderElectionResourceLock: resourcelock.LeasesResourceLock,
+		LeaderElectionNamespace:    leaderElectionNamespace,
+		LeaseDuration:              &leaderElectionLeaseDuration,
+		RenewDeadline:              &leaderElectionRenewDeadline,
+		RetryPeriod:                &leaderElectionRetryPeriod,
+		CertDir:                    webhookCertDir,
+		Namespace:                  watchNamespace,
 	})
 	if err != nil {
 		setupLog.Error(err, "unable to start manager")