nfd-gc: use paging when listing CRs

List NodeFeature and NodeResourceTopology objects in pages of 200 items.
This reduces memory consumption and eliminates timeouts (on the
apiserver side) in big clusters of thousands of nodes.

pkg/nfd-gc/nfd-gc.go

@@ -26,6 +26,7 @@ import (
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/labels"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/util/sets"
 	metadataclient "k8s.io/client-go/metadata"
 	"k8s.io/client-go/metadata/metadatainformer"
@@ -152,37 +153,47 @@ func (n *nfdGarbageCollector) garbageCollect() {
 		nodeNames.Insert(meta.Name)
 	}
 
-	// Handle NodeFeature objects
+	listAndHandle := func(gvr schema.GroupVersionResource, handler func(metav1.PartialObjectMetadata)) {
-	objMetas, err := n.client.Resource(gvrNF).List(context.TODO(), metav1.ListOptions{})
+		opts := metav1.ListOptions{
+			Limit: 200,
+		}
+		for {
+			rsp, err := n.client.Resource(gvr).List(context.TODO(), opts)
 			if errors.IsNotFound(err) {
-		klog.V(2).InfoS("NodeFeature CRD does not exist")
+				klog.V(2).InfoS("resource does not exist", "resource", gvr)
+				break
 			} else if err != nil {
-		klog.ErrorS(err, "failed to list NodeFeature objects")
+				klog.ErrorS(err, "failed to list objects", "resource", gvr)
-	} else {
+				break
-		for _, nf := range objMetas.Items {
-			nodeName, ok := nf.GetLabels()[nfdv1alpha1.NodeFeatureObjNodeNameLabel]
-			if !ok {
-				klog.InfoS("node name label missing from NodeFeature object", "nodefeature", klog.KObj(&nf))
 			}
-			if !nodeNames.Has(nodeName) {
+			for _, item := range rsp.Items {
-				n.deleteNodeFeature(nf.Namespace, nf.Name)
+				handler(item)
 			}
+
+			if rsp.ListMeta.Continue == "" {
+				break
+			}
+			opts.Continue = rsp.ListMeta.Continue
 		}
 	}
 
+	// Handle NodeFeature objects
+	listAndHandle(gvrNF, func(meta metav1.PartialObjectMetadata) {
+		nodeName, ok := meta.GetLabels()[nfdv1alpha1.NodeFeatureObjNodeNameLabel]
+		if !ok {
+			klog.InfoS("node name label missing from NodeFeature object", "nodefeature", klog.KObj(&meta))
+		}
+		if !nodeNames.Has(nodeName) {
+			n.deleteNodeFeature(meta.Namespace, meta.Name)
+		}
+	})
+
 	// Handle NodeResourceTopology objects
-	objMetas, err = n.client.Resource(gvrNRT).List(context.TODO(), metav1.ListOptions{})
+	listAndHandle(gvrNRT, func(meta metav1.PartialObjectMetadata) {
-	if errors.IsNotFound(err) {
+		if !nodeNames.Has(meta.Name) {
-		klog.V(2).InfoS("NodeResourceTopology CRD does not exist")
+			n.deleteNRT(meta.Name)
-	} else if err != nil {
-		klog.ErrorS(err, "failed to list NodeResourceTopology objects")
-	} else {
-		for _, nrt := range objMetas.Items {
-			if !nodeNames.Has(nrt.Name) {
-				n.deleteNRT(nrt.Name)
-			}
-		}
 		}
+	})
 }
 
 // periodicGC runs garbage collector at every gcPeriod to make sure we haven't missed any node