add configurable pagination to nfd-master

Author: ivelichkovich

cmd/nfd-master/main.go

@@ -140,6 +140,8 @@ func initFlags(flagset *flag.FlagSet) (*master.Args, *master.ConfigOverrideArgs)
 	flagset.Var(overrides.ResyncPeriod, "resync-period", "Specify the NFD API controller resync period.")
 	overrides.NfdApiParallelism = flagset.Int("nfd-api-parallelism", 10, "Defines the maximum number of goroutines responsible of updating nodes. "+
 		"Can be used for the throttling mechanism.")
+	overrides.InformerPageSize = flagset.Int64("informer-page-size", 200,
+		"The list size to use when listing NodeFeature objects to sync informer cache.")
 
 	return args, overrides
 }

deployment/components/master-config/nfd-master.conf.example

@@ -2,6 +2,7 @@
 # extraLabelNs: ["added.ns.io","added.kubernets.io"]
 # denyLabelNs: ["denied.ns.io","denied.kubernetes.io"]
 # enableTaints: false
+# informerPageSize: 200
 # labelWhiteList: "foo"
 # resyncPeriod: "2h"
 # restrictions:

deployment/helm/node-feature-discovery/values.yaml

@@ -28,6 +28,7 @@ master:
     # extraLabelNs: ["added.ns.io","added.kubernets.io"]
     # denyLabelNs: ["denied.ns.io","denied.kubernetes.io"]
     # enableTaints: false
+    # informerPageSize: 200
     # labelWhiteList: "foo"
     # resyncPeriod: "2h"
     # restrictions:

docs/reference/master-commandline-reference.md

@@ -173,6 +173,21 @@ Example:
 nfd-master -deny-label-ns=*.vendor.com,vendor-2.io
 ```
 
+### -informer-page-size
+
+The `-informer-page-size` flag is used to control pagination
+during informer cache sync on nfd-master startup.
+This is useful to control load on api-server/etcd as listing
+NodeFeature objects can be expensive, especially in large clusters.
+
+Default: 200
+
+Example:
+
+```bash
+nfd-master -informer-page-size=20
+```
+
 ### -config
 
 The `-config` flag specifies the path of the nfd-master configuration file to

docs/reference/master-configuration-reference.md

@@ -180,6 +180,21 @@ Example:
 nfdApiParallelism: 1
 ```
 
+## informerPageSize
+
+The `informerPageSize` option is used to control pagination
+during informer cache sync on nfd-master startup.
+This is useful to control load on api-server/etcd as listing
+NodeFeature objects can be expensive, especially in large clusters.
+
+Default: 200
+
+Example:
+
+```yaml
+informerPageSize: 50
+```
+
 ## klog
 
 The following options specify the logger configuration. Most of which can be

docs/usage/nfd-master.md

@@ -84,3 +84,11 @@ If you have RBAC authorization enabled (as is the default e.g. with clusters
 initialized with kubeadm) you need to configure the appropriate ClusterRoles,
 ClusterRoleBindings and a ServiceAccount for NFD to create node
 labels. The provided template will configure these for you.
+
+## Informer List Pagination
+
+When NFD Master starts up it starts an informer on the nodefeatures resources.
+These resources can be large and in a large cluster this initial list call
+to sync the informer cache can be expensive and heavy on api-server/etcd.
+You can use the `informer-list-size` argument to NFD master to
+control pagination size to help control the load during NFD-Master restart.

pkg/nfd-master/nfd-api-controller.go

@@ -56,6 +56,7 @@ type nfdApiControllerOptions struct {
 	ResyncPeriod                 time.Duration
 	K8sClient                    k8sclient.Interface
 	NodeFeatureNamespaceSelector *metav1.LabelSelector
+	ListSize                     int64
 }
 
 func init() {
@@ -95,11 +96,19 @@ func newNfdController(config *restclient.Config, nfdApiControllerOptions nfdApiC
 		// Tweak list opts on initial sync to avoid timeouts on the apiserver.
 		// NodeFeature objects are huge and the Kubernetes apiserver
 		// (v1.30) experiences http handler timeouts when the resource
-		// version is set to some non-empty value (TODO: find out why).
+		// version is set to some non-empty value
+		// https://github.com/kubernetes/kubernetes/blob/ace55542575fb098b3e413692bbe2bc20d2348ba/staging/src/k8s.io/apiserver/pkg/storage/cacher/cacher.go#L600-L616 if you set resource version to 0
+		// it serves the request from apiservers cache and doesn't use pagination otherwise pagination will default to 500
+		// so that's why this is required on large clusters
+		// So by setting this we're making it go to ETCD instead of from api-server cache, there's some WIP in k/k
+		// that seems to imply they're working on improving this behavior where you'll be able to paginate from apiserver cache
+		// it's not supported yet (2/2025), would be good to track this though kubernetes/kubernetes#108003
 		if opts.ResourceVersion == "0" {
 			opts.ResourceVersion = ""
 		}
+		opts.Limit = nfdApiControllerOptions.ListSize // value of 0 disables pagination
 	}
+
 	featureInformer := nfdinformersv1alpha1.New(informerFactory, "", tweakListOpts).NodeFeatures()
 	if _, err := featureInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(obj interface{}) {

pkg/nfd-master/nfd-master.go

@@ -91,6 +91,7 @@ type NFDConfig struct {
 	NfdApiParallelism int
 	Klog              klogutils.KlogConfigOpts
 	Restrictions      Restrictions
+	InformerPageSize  int64
 }
 
 // LeaderElectionConfig contains the configuration for leader election
@@ -109,6 +110,7 @@ type ConfigOverrideArgs struct {
 	NoPublish         *bool
 	ResyncPeriod      *utils.DurationVal
 	NfdApiParallelism *int
+	InformerPageSize  *int64
 }
 
 // Args holds command line arguments
@@ -121,6 +123,7 @@ type Args struct {
 	Prune                bool
 	Options              string
 	EnableLeaderElection bool
+	MetricsPort          int
 
 	Overrides ConfigOverrideArgs
 }
@@ -243,6 +246,7 @@ func newDefaultConfig() *NFDConfig {
 		NfdApiParallelism: 10,
 		EnableTaints:      false,
 		ResyncPeriod:      utils.DurationVal{Duration: time.Duration(1) * time.Hour},
+		InformerPageSize:  200,
 		LeaderElection: LeaderElectionConfig{
 			LeaseDuration: utils.DurationVal{Duration: time.Duration(15) * time.Second},
 			RetryPeriod:   utils.DurationVal{Duration: time.Duration(2) * time.Second},
@@ -1187,6 +1191,9 @@ func (m *nfdMaster) configure(filepath string, overrides string) error {
 	if m.args.Overrides.NfdApiParallelism != nil {
 		c.NfdApiParallelism = *m.args.Overrides.NfdApiParallelism
 	}
+	if m.args.Overrides.InformerPageSize != nil {
+		c.InformerPageSize = *m.args.Overrides.InformerPageSize
+	}
 
 	if c.NfdApiParallelism <= 0 {
 		return fmt.Errorf("the maximum number of concurrent labelers should be a non-zero positive number")
@@ -1293,6 +1300,7 @@ func (m *nfdMaster) startNfdApiController() error {
 		K8sClient:                    m.k8sClient,
 		NodeFeatureNamespaceSelector: m.config.Restrictions.NodeFeatureNamespaceSelector,
 		DisableNodeFeatureGroup:      !nfdfeatures.NFDFeatureGate.Enabled(nfdfeatures.NodeFeatureGroupAPI),
+		ListSize:                     m.config.InformerPageSize,
 	})
 	if err != nil {
 		return fmt.Errorf("failed to initialize CRD controller: %w", err)