Add health and readyness probes

and use the new ctrl.NewManager, which is an alias of manager.Manager to
create the manager.

Various options are defined at
https://godocs.io/sigs.k8s.io/controller-runtime/pkg/manager#Options.

Health and readyness logic is not implemented yet but are added for
future usage.

Part of epic: submariner-io/enhancements#81

Signed-off-by: Janki Chhatbar <[email protected]>

main.go

@@ -43,11 +43,12 @@ import (
 	"k8s.io/client-go/dynamic"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
+	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
 	"sigs.k8s.io/controller-runtime/pkg/client/config"
+	"sigs.k8s.io/controller-runtime/pkg/healthz"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
-	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
 )
 
@@ -73,7 +74,15 @@ func init() {
 	flag.BoolVar(&help, "help", help, "Print usage options")
 }
 
+// nolint:gocyclo // No further refactors necessary
 func main() {
+	var enableLeaderElection bool
+	var probeAddr string
+	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
+	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
+		"Enable leader election for controller manager. "+
+			"Enabling this will ensure there is only one active controller manager.")
+
 	kzerolog.AddFlags(nil)
 	flag.Parse()
 
@@ -139,11 +148,14 @@ func main() {
 	// +kubebuilder:scaffold:scheme
 
 	// Create a new Cmd to provide shared dependencies and start components
-	mgr, err := manager.New(cfg, manager.Options{
-		Namespace:          namespace,
-		MapperProvider:     apiutil.NewDiscoveryRESTMapper,
-		MetricsBindAddress: fmt.Sprintf("%s:%d", metricsHost, metricsPort),
-		Scheme:             scheme,
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
+		Scheme:                 scheme,
+		MetricsBindAddress:     fmt.Sprintf("%s:%d", metricsHost, metricsPort),
+		HealthProbeBindAddress: probeAddr,
+		LeaderElection:         enableLeaderElection,
+		LeaderElectionID:       "2a1e5b0d.submariner.io",
+		Namespace:              namespace, // namespaced-scope when the value is not an empty string
+		MapperProvider:         apiutil.NewDiscoveryRESTMapper,
 	})
 	if err != nil {
 		log.Error(err, "unable to start manager")
@@ -203,6 +215,16 @@ func main() {
 
 	// +kubebuilder:scaffold:builder
 
+	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
+		log.Error(err, "unable to set up health check")
+		os.Exit(1) // We might not want to exit here if healthchecks are not setup.
+	}
+
+	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
+		log.Error(err, "unable to set up ready check")
+		os.Exit(1) // We might not want to exit here if ready checks are not setup.
+	}
+
 	// Start the Cmd
 	log.Info("Starting the Cmd.")