Reduce cache memory footprint by optimizing what we store

cmd/gpu-operator/cache.go

@@ -0,0 +1,96 @@
+/**
+# Copyright (c) NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package main
+
+import (
+	"fmt"
+	"maps"
+
+	apiimagev1 "github.com/openshift/api/image/v1"
+	corev1 "k8s.io/api/core/v1"
+	resourcev1 "k8s.io/api/resource/v1"
+	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/fields"
+	"k8s.io/client-go/rest"
+	"sigs.k8s.io/controller-runtime/pkg/cache"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
+
+	"github.com/NVIDIA/gpu-operator/controllers"
+	"github.com/NVIDIA/gpu-operator/internal/consts"
+)
+
+func newOperatorCache(config *rest.Config, options cache.Options) (cache.Cache, error) {
+	// ByObject scopes are resolved eagerly, even if no informer is ever used.
+	// The manager supplies its shared scheme and discovery mapper before calling
+	// this factory, so optional APIs need not become startup requirements.
+	options.ByObject = maps.Clone(options.ByObject)
+	for object := range options.ByObject {
+		switch object.(type) {
+		case *apiimagev1.ImageStream, *resourcev1.ResourceClaim:
+		default:
+			continue
+		}
+		_, err := apiutil.IsObjectNamespaced(object, options.Scheme, options.Mapper)
+		if meta.IsNoMatchError(err) {
+			delete(options.ByObject, object)
+		} else if err != nil {
+			// An unavailable API server is not evidence that an API is absent.
+			return nil, fmt.Errorf("discover optional cache API %T: %w", object, err)
+		}
+	}
+	return cache.New(config, options)
+}
+
+func operatorCacheOptions(operatorNamespace string) cache.Options {
+	stripManagedFields := cache.TransformStripManagedFields()
+	// DRA teardown checks inspect Pods and their ResourceClaims across the existing
+	// cache namespaces. Preserve that scope independently of operand-only resources.
+	workloadNamespaces := map[string]cache.Config{
+		operatorNamespace:         {},
+		consts.OpenshiftNamespace: {},
+	}
+	return cache.Options{
+		DefaultNamespaces: map[string]cache.Config{operatorNamespace: {}},
+		DefaultTransform:  stripManagedFields,
+		ByObject: map[client.Object]cache.ByObject{
+			&corev1.Node{}: {
+				// Keep all nodes for GPU discovery and label cleanup, but omit the
+				// image inventory, which no operator consumer uses.
+				Transform: func(in any) (any, error) {
+					if node, ok := in.(*corev1.Node); ok {
+						node.Status.Images = nil
+					}
+					return stripManagedFields(in)
+				},
+			},
+			&corev1.Pod{}:               {Namespaces: workloadNamespaces},
+			&resourcev1.ResourceClaim{}: {Namespaces: workloadNamespaces},
+			&apiextensionsv1.CustomResourceDefinition{}: {
+				// crdExists only checks ServiceMonitor availability. Apply the
+				// selector to LIST/WATCH so other CRD schemas never enter the cache.
+				Field: fields.OneTermEqualSelector("metadata.name", controllers.ServiceMonitorCRDName),
+			},
+			&apiimagev1.ImageStream{}: {
+				// Only the Driver Toolkit ImageStream is read from openshift.
+				Namespaces: map[string]cache.Config{consts.OpenshiftNamespace: {}},
+				Field:      fields.OneTermEqualSelector("metadata.name", "driver-toolkit"),
+			},
+		},
+	}
+}