Prevent LoadBalancer updates on follower.

changelogs/unreleased/6872-tsaarni-small.md

@@ -0,0 +1 @@
+Fixed a memory leak in Contour follower instance due to unprocessed LoadBalancer status updates.

cmd/contour/ingressstatus.go

@@ -22,6 +22,7 @@
 	core_v1 "k8s.io/api/core/v1"
 	networking_v1 "k8s.io/api/networking/v1"
 	"k8s.io/apimachinery/pkg/types"
+	client_go_cache "k8s.io/client-go/tools/cache"
 	"sigs.k8s.io/controller-runtime/pkg/cache"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	gatewayapi_v1 "sigs.k8s.io/gateway-api/apis/v1"
@@ -55,13 +56,45 @@
 	statusUpdater     k8s.StatusUpdater
 	ingressClassNames []string
 	gatewayRef        *types.NamespacedName
+	statusAddress     string
+	serviceName       string
+	serviceNamespace  string
 }
 
 func (isw *loadBalancerStatusWriter) NeedLeaderElection() bool {
 	return true
 }
 
 func (isw *loadBalancerStatusWriter) Start(ctx context.Context) error {
+	// Register an informer to watch envoy's service if we haven't been given static details.
+	// The informer is registered only after leader election to prevent events from being sent before the status writer
+	// is ready to process them.
+	if lbAddress := isw.statusAddress; len(lbAddress) > 0 {
+		isw.log.WithField("loadbalancer-address", lbAddress).Info("Using supplied information for Ingress status")
+		isw.lbStatus <- parseStatusFlag(lbAddress)
+	} else {
+		// Register Service informer to watch for status updates.
+		var serviceHandler client_go_cache.ResourceEventHandler = &k8s.ServiceStatusLoadBalancerWatcher{
+			ServiceName: isw.serviceName,
+			LBStatus:    isw.lbStatus,
+			Log:         isw.log.WithField("context", "serviceStatusLoadBalancerWatcher"),
+		}
+		var handler client_go_cache.ResourceEventHandler = serviceHandler
+		if isw.serviceNamespace != "" {
+			serviceHandler = k8s.NewNamespaceFilter([]string{isw.serviceNamespace}, handler)
+		}
+		inf, err := isw.cache.GetInformer(ctx, &core_v1.Service{})
+		if err != nil {
+			isw.log.WithError(err).Fatal("failed to get Service informer")
+			return err
+		}
+		_, err = inf.AddEventHandler(serviceHandler)
+		if err != nil {
+			isw.log.WithError(err).Fatal("failed to add Service event handler")
+			return err
+		}
+	}
+
 	u := &k8s.StatusAddressUpdater{
 		Logger: func() logrus.FieldLogger {
 			// Configure the StatusAddressUpdater logger.

cmd/contour/serve.go

@@ -700,36 +700,14 @@
 		ingressClassNames: ingressClassNames,
 		gatewayRef:        gatewayRef,
 		statusUpdater:     sh.Writer(),
+		statusAddress:     contourConfiguration.Ingress.StatusAddress,
+		serviceName:       contourConfiguration.Envoy.Service.Name,
+		serviceNamespace:  contourConfiguration.Envoy.Service.Namespace,
 	}
 	if err := s.mgr.Add(lbsw); err != nil {
 		return err
 	}
 
-	// Register an informer to watch envoy's service if we haven't been given static details.
-	if lbAddress := contourConfiguration.Ingress.StatusAddress; len(lbAddress) > 0 {
-		s.log.WithField("loadbalancer-address", lbAddress).Info("Using supplied information for Ingress status")
-		lbsw.lbStatus <- parseStatusFlag(lbAddress)
-	} else {
-		serviceHandler := &k8s.ServiceStatusLoadBalancerWatcher{
-			ServiceName: contourConfiguration.Envoy.Service.Name,
-			LBStatus:    lbsw.lbStatus,
-			Log:         s.log.WithField("context", "serviceStatusLoadBalancerWatcher"),
-		}
-
-		var handler cache.ResourceEventHandler = serviceHandler
-		if contourConfiguration.Envoy.Service.Namespace != "" {
-			handler = k8s.NewNamespaceFilter([]string{contourConfiguration.Envoy.Service.Namespace}, handler)
-		}
-
-		if err := s.informOnResource(&core_v1.Service{}, handler); err != nil {
-			s.log.WithError(err).WithField("resource", "services").Fatal("failed to create informer")
-		}
-
-		s.log.WithField("envoy-service-name", contourConfiguration.Envoy.Service.Name).
-			WithField("envoy-service-namespace", contourConfiguration.Envoy.Service.Namespace).
-			Info("Watching Service for Ingress status")
-	}
-
 	xdsServer := &xdsServer{
 		log:             s.log,
 		registry:        s.registry,