fix(performance): scope Deployment/StatefulSet cache to operator-managed objects [RHDHBUGS-3569]

cmd/main.go

@@ -10,6 +10,7 @@ import (
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 	"sigs.k8s.io/controller-runtime/pkg/metrics/filters"
 
+	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -27,6 +28,7 @@ import (
 	bsv1 "github.com/redhat-developer/rhdh-operator/api/v1alpha5"
 
 	"github.com/redhat-developer/rhdh-operator/internal/controller"
+	"github.com/redhat-developer/rhdh-operator/pkg/utils"
 
 	openshift "github.com/openshift/api/route/v1"
 	//+kubebuilder:scaffold:imports
@@ -137,10 +139,34 @@ func main() {
 	// With many resources, managedFields can consume 70%+ of the informer cache heap.
 	mgrOpts.Cache.DefaultTransform = cache.TransformStripManagedFields()
 
-	// Configure cache to only watch labeled Secrets and ConfigMaps if flag is enabled
+	// Restrict Deployment/StatefulSet cache to operator-managed objects only.
+	// The operator only needs Deployments/StatefulSets it creates, and those always
+	// carry app.kubernetes.io/name=backstage. Without this filter, the metadata
+	// informers cache every Deployment and StatefulSet cluster-wide, which on
+	// large multi-tenant clusters consumes hundreds of MB of heap.
+	backstageLabelSelector, err := metav1.LabelSelectorAsSelector(&metav1.LabelSelector{
+		MatchLabels: map[string]string{
+			utils.BackstageAppLabel: utils.BackstageAppName,
+		},
+	})
+	if err != nil {
+		setupLog.Error(err, "failed to create backstage label selector")
+		os.Exit(1)
+	}
+
+	mgrOpts.Cache.ByObject = map[client.Object]cache.ByObject{
+		&appsv1.Deployment{}: {
+			Label: backstageLabelSelector,
+		},
+		&appsv1.StatefulSet{}: {
+			Label: backstageLabelSelector,
+		},
+	}
+
+	// Optionally restrict Secret/ConfigMap cache to labeled objects.
 	if enableCacheLabelFilter {
 		setupLog.Info("Enabling cache label filter for Secrets and ConfigMaps")
-		labelSelector, err := metav1.LabelSelectorAsSelector(&metav1.LabelSelector{
+		extConfigLabelSelector, err := metav1.LabelSelectorAsSelector(&metav1.LabelSelector{
 			MatchLabels: map[string]string{
 				"rhdh.redhat.com/external-config": "true",
 			},
@@ -150,13 +176,11 @@ func main() {
 			os.Exit(1)
 		}
 
-		mgrOpts.Cache.ByObject = map[client.Object]cache.ByObject{
-			&corev1.Secret{}: {
-				Label: labelSelector,
-			},
-			&corev1.ConfigMap{}: {
-				Label: labelSelector,
-			},
+		mgrOpts.Cache.ByObject[&corev1.Secret{}] = cache.ByObject{
+			Label: extConfigLabelSelector,
+		}
+		mgrOpts.Cache.ByObject[&corev1.ConfigMap{}] = cache.ByObject{
+			Label: extConfigLabelSelector,
 		}
 	}
 

internal/controller/watchers.go

@@ -7,6 +7,7 @@ import (
 	"github.com/redhat-developer/rhdh-operator/api"
 	"github.com/redhat-developer/rhdh-operator/pkg/model"
 	"github.com/redhat-developer/rhdh-operator/pkg/utils"
+	appsv1 "k8s.io/api/apps/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -74,53 +75,32 @@ func (r *BackstageReconciler) addWatchers(b *builder.Builder) error {
 				}))
 	}
 
-	// Watch Deployment for the Backstage CR status if enabled
-	labelPred, err := predicate.LabelSelectorPredicate(metav1.LabelSelector{
-		MatchExpressions: []metav1.LabelSelectorRequirement{
-			{
-				Key:      utils.BackstageAppLabel,
-				Values:   []string{utils.BackstageAppName},
-				Operator: metav1.LabelSelectorOpIn,
-			},
+	// Watch operator-owned Deployments and StatefulSets for status tracking.
+	// Owns() maps events back to the owning Backstage CR via ownerReferences.
+	logEvent := func(eventType string, obj client.Object) {
+		log.Log.V(1).Info("enqueuing reconcile on change of",
+			"event", eventType,
+			"kind", obj.GetObjectKind().GroupVersionKind().Kind,
+			"name", obj.GetName(),
+			"namespace", obj.GetNamespace())
+	}
+	commonPreds := builder.WithPredicates(predicate.Funcs{
+		CreateFunc: func(e event.CreateEvent) bool {
+			logEvent("create", e.Object)
+			return true
+		},
+		UpdateFunc: func(e event.UpdateEvent) bool {
+			logEvent("update", e.ObjectNew)
+			return true
+		},
+		DeleteFunc: func(e event.DeleteEvent) bool {
+			logEvent("delete", e.Object)
+			return true
 		},
 	})
-	if err != nil {
-		return fmt.Errorf("failed to construct the predicate for backstage deployment. This should not happen: %w", err)
-	}
 
-	commonPreds := builder.WithPredicates(labelPred, predicate.Funcs{
-		DeleteFunc: func(e event.DeleteEvent) bool { return true },
-		UpdateFunc: func(e event.UpdateEvent) bool { return true },
-		CreateFunc: func(e event.CreateEvent) bool { return true },
-	})
-
-	metaFor := func(kind string) *metav1.PartialObjectMetadata {
-		m := &metav1.PartialObjectMetadata{}
-		m.SetGroupVersionKind(schema.GroupVersionKind{
-			Group:   "apps",
-			Version: "v1",
-			Kind:    kind,
-		})
-		return m
-	}
-
-	// Deployment
-	b.WatchesMetadata(
-		metaFor("Deployment"),
-		handler.EnqueueRequestsFromMapFunc(func(ctx context.Context, o client.Object) []reconcile.Request {
-			return r.requestByAppLabels(ctx, o)
-		}),
-		commonPreds,
-	)
-
-	// StatefulSet
-	b.WatchesMetadata(
-		metaFor("StatefulSet"),
-		handler.EnqueueRequestsFromMapFunc(func(ctx context.Context, o client.Object) []reconcile.Request {
-			return r.requestByAppLabels(ctx, o)
-		}),
-		commonPreds,
-	)
+	b.Owns(&appsv1.Deployment{}, commonPreds).
+		Owns(&appsv1.StatefulSet{}, commonPreds)
 
 	return nil
 }
@@ -183,16 +163,3 @@ func (r *BackstageReconciler) requestByExtConfigLabel(ctx context.Context, objec
 	return []reconcile.Request{{NamespacedName: types.NamespacedName{Name: backstage.Name, Namespace: object.GetNamespace()}}}
 
 }
-
-// requestByAppLabels returns a request with current Namespace and Backstage Object name taken from label
-func (r *BackstageReconciler) requestByAppLabels(ctx context.Context, object client.Object) []reconcile.Request {
-	lg := log.FromContext(ctx)
-
-	backstageName := object.GetLabels()[utils.BackstageInstanceLabel]
-	if object.GetLabels()[utils.BackstageAppLabel] == "" || backstageName == "" {
-		return []reconcile.Request{}
-	}
-
-	lg.V(1).Info("enqueuing reconcile on change of ", "kind: ", object.GetObjectKind().GroupVersionKind().Kind, "name: ", object.GetName(), "namespace: ", object.GetNamespace())
-	return []reconcile.Request{{NamespacedName: types.NamespacedName{Name: backstageName, Namespace: object.GetNamespace()}}}
-}