Revert "feat: remove leader election for operator (opendatahub-io#1000)…

…" (opendatahub-io#1153)

* Revert "feat: remove leader election for operator (opendatahub-io#1000)"
- we need have leader election enabled for Operator
This reverts commit 3610b0b.
- remove files (configmap) not in use
---------
Signed-off-by: Wen Zhou <wenzhou@redhat.com>

bundle/manifests/opendatahub-operator.clusterserviceversion.yaml

@@ -1701,6 +1701,7 @@ spec:
               - args:
                 - --health-probe-bind-address=:8081
                 - --metrics-bind-address=0.0.0.0:8080
+                - --leader-elect
                 command:
                 - /manager
                 env:

config/default/manager_auth_proxy_patch.yaml

@@ -13,3 +13,4 @@ spec:
         args:
         - "--health-probe-bind-address=:8081"
         - "--metrics-bind-address=0.0.0.0:8080"
+        - "--leader-elect"

config/manager/kustomization.yaml.in

@@ -4,10 +4,6 @@ resources:
 generatorOptions:
   disableNameSuffixHash: true
 
-configMapGenerator:
-- files:
-  - controller_manager_config.yaml
-  name: manager-config
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 images:

config/manager/manager.yaml

@@ -47,6 +47,7 @@ spec:
           - name: DEFAULT_MANIFESTS_PATH
             value: /opt/manifests
         args:
+        - --leader-elect
         - --operator-name=opendatahub
         image: controller:latest
         imagePullPolicy: Always

main.go

@@ -98,6 +98,7 @@ func init() { //nolint:gochecknoinits
 
 func main() { //nolint:funlen
 	var metricsAddr string
+	var enableLeaderElection bool
 	var probeAddr string
 	var dscApplicationsNamespace string
 	var dscMonitoringNamespace string
@@ -106,6 +107,9 @@ func main() { //nolint:funlen
 
 	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
 	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.")
 	flag.StringVar(&dscApplicationsNamespace, "dsc-applications-namespace", "opendatahub", "The namespace where data science cluster"+
 		"applications will be deployed")
 	flag.StringVar(&dscMonitoringNamespace, "dsc-monitoring-namespace", "opendatahub", "The namespace where data science cluster"+
@@ -119,12 +123,24 @@ func main() { //nolint:funlen
 
 	// root context
 	ctx := ctrl.SetupSignalHandler()
-
-	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{ // single pod does not need to have LeaderElection
+	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
 		Scheme:                 scheme,
 		MetricsBindAddress:     metricsAddr,
 		Port:                   9443,
 		HealthProbeBindAddress: probeAddr,
+		LeaderElection:         enableLeaderElection,
+		LeaderElectionID:       "07ed84f7.opendatahub.io",
+		// LeaderElectionReleaseOnCancel defines if the leader should step down voluntarily
+		// when the Manager ends. This requires the binary to immediately end when the
+		// Manager is stopped, otherwise, this setting is unsafe. Setting this significantly
+		// speeds up voluntary leader transitions as the new leader don't have to wait
+		// LeaseDuration time first.
+		//
+		// In the default scaffold provided, the program ends immediately after
+		// the manager stops, so would be fine to enable this option. However,
+		// if you are doing or is intended to do any operation such as perform cleanups
+		// after the manager stops then its usage might be unsafe.
+		// LeaderElectionReleaseOnCancel: true,
 	})
 	if err != nil {
 		setupLog.Error(err, "unable to start manager")