Add leader election lease related flags (#421)

Add flags to the manager to be able to set various leader election
configurations. These leader-election flags are supported by the
[manager](https://pkg.go.dev/sigs.k8s.io/controller-runtime/pkg/manager#Options).
Moreover most projects in the cluster-api umbrella already support them.

Co-authored-by: Mohamed Chiheb Ben Jemaa <[email protected]>

Author: nikParasyr

cmd/main.go

@@ -24,6 +24,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"time"
 
 	"github.com/go-logr/logr"
 	"github.com/luthermonson/go-proxmox"
@@ -59,10 +60,13 @@ var (
 	scheme   = runtime.NewScheme()
 	setupLog = ctrl.Log.WithName("setup")
 
-	metricsAddr          string
-	enableLeaderElection bool
-	enableWebhooks       bool
-	probeAddr            string
+	metricsAddr                 string
+	enableLeaderElection        bool
+	leaderElectionLeaseDuration time.Duration
+	leaderElectionRenewDeadline time.Duration
+	leaderElectionRetryPeriod   time.Duration
+	enableWebhooks              bool
+	probeAddr                   string
 
 	// ProxmoxURL env variable that defines the Proxmox host.
 	ProxmoxURL string
@@ -101,6 +105,9 @@ func main() {
 		}),
 		HealthProbeBindAddress: probeAddr,
 		LeaderElection:         enableLeaderElection,
+		LeaseDuration:          &leaderElectionLeaseDuration,
+		RenewDeadline:          &leaderElectionRenewDeadline,
+		RetryPeriod:            &leaderElectionRetryPeriod,
 		LeaderElectionID:       "controller-leader-elect-capmox",
 		// LeaderElectionReleaseOnCancel defines if the leader should step down voluntarily
 		// when the Manager ends. This requires the binary to immediately end when the
@@ -232,6 +239,12 @@ func initFlagsAndEnv(fs *pflag.FlagSet) {
 	fs.BoolVar(&enableLeaderElection, "leader-elect", false,
 		"Enable leader election for controller manager. "+
 			"Enabling this will ensure there is only one active controller manager.")
+	fs.DurationVar(&leaderElectionLeaseDuration, "leader-elect-lease-duration", 15*time.Second,
+		"Interval at which non-leader candidates will wait to force acquire leadership (duration string)")
+	fs.DurationVar(&leaderElectionRenewDeadline, "leader-elect-renew-deadline", 10*time.Second,
+		"Duration that the leading controller manager will retry refreshing leadership before giving up (duration string)")
+	fs.DurationVar(&leaderElectionRetryPeriod, "leader-elect-retry-period", 2*time.Second,
+		"Duration the LeaderElector clients should wait between tries of actions (duration string)")
 	fs.BoolVar(&enableWebhooks, "enable-webhooks", true,
 		"If true, run webhook server alongside manager")