Add FeatureGate framework to handle new features

Signed-off-by: Carlos Eduardo Arango Gutierrez <eduardoa@nvidia.com>

cmd/nfd-master/main.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/klog/v2"
 	klogutils "sigs.k8s.io/node-feature-discovery/pkg/utils/klog"
 
+	"sigs.k8s.io/node-feature-discovery/pkg/features"
 	master "sigs.k8s.io/node-feature-discovery/pkg/nfd-master"
 	"sigs.k8s.io/node-feature-discovery/pkg/utils"
 	"sigs.k8s.io/node-feature-discovery/pkg/version"
@@ -42,6 +43,12 @@ func main() {
 	printVersion := flags.Bool("version", false, "Print version and exit.")
 
 	args, overrides := initFlags(flags)
+	// Add FeatureGates flag
+	if err := utils.NFDMutableFeatureGate.Add(features.DefaultNFDFeatureGates); err != nil {
+		klog.ErrorS(err, "failed to add default feature gates")
+		os.Exit(1)
+	}
+	utils.NFDMutableFeatureGate.AddFlag(flags)
 
 	_ = flags.Parse(os.Args[1:])
 	if len(flags.Args()) > 0 {
@@ -74,8 +81,6 @@ func main() {
 			args.Overrides.ResyncPeriod = overrides.ResyncPeriod
 		case "nfd-api-parallelism":
 			args.Overrides.NfdApiParallelism = overrides.NfdApiParallelism
-		case "enable-nodefeature-api":
-			klog.InfoS("-enable-nodefeature-api is deprecated, will be removed in a future release along with the deprecated gRPC API")
 		case "ca-file":
 			klog.InfoS("-ca-file is deprecated, will be removed in a future release along with the deprecated gRPC API")
 		case "cert-file":
@@ -134,9 +139,6 @@ func initFlags(flagset *flag.FlagSet) (*master.Args, *master.ConfigOverrideArgs)
 		"Config file to use.")
 	flagset.StringVar(&args.Kubeconfig, "kubeconfig", "",
 		"Kubeconfig to use")
-	flagset.BoolVar(&args.EnableNodeFeatureApi, "enable-nodefeature-api", true,
-		"Enable the NodeFeature CRD API for receiving node features. This will automatically disable the gRPC communication."+
-			" DEPRECATED: will be removed in a future release along with the deprecated gRPC API.")
 	flagset.BoolVar(&args.CrdController, "featurerules-controller", true,
 		"Enable NFD CRD API controller. DEPRECATED: use -crd-controller instead")
 	flagset.BoolVar(&args.CrdController, "crd-controller", true,

cmd/nfd-worker/main.go

@@ -24,6 +24,7 @@ import (
 	"k8s.io/klog/v2"
 	klogutils "sigs.k8s.io/node-feature-discovery/pkg/utils/klog"
 
+	"sigs.k8s.io/node-feature-discovery/pkg/features"
 	worker "sigs.k8s.io/node-feature-discovery/pkg/nfd-worker"
 	"sigs.k8s.io/node-feature-discovery/pkg/utils"
 	"sigs.k8s.io/node-feature-discovery/pkg/version"
@@ -87,6 +88,12 @@ func main() {
 
 func parseArgs(flags *flag.FlagSet, osArgs ...string) *worker.Args {
 	args, overrides := initFlags(flags)
+	// Add FeatureGates flag
+	if err := utils.NFDMutableFeatureGate.Add(features.DefaultNFDFeatureGates); err != nil {
+		klog.ErrorS(err, "failed to add default feature gates")
+		os.Exit(1)
+	}
+	utils.NFDMutableFeatureGate.AddFlag(flags)
 
 	_ = flags.Parse(osArgs)
 	if len(flags.Args()) > 0 {
@@ -124,9 +131,6 @@ func initFlags(flagset *flag.FlagSet) (*worker.Args, *worker.ConfigOverrideArgs)
 	flagset.StringVar(&args.KeyFile, "key-file", "",
 		"Private key matching -cert-file."+
 			" DEPRECATED: will be removed in a future release along with the deprecated gRPC API.")
-	flagset.BoolVar(&args.EnableNodeFeatureApi, "enable-nodefeature-api", true,
-		"Enable the NodeFeature CRD API for communicating with nfd-master. This will automatically disable the gRPC communication."+
-			" DEPRECATED: will be removed in a future release along with the deprecated gRPC API.")
 	flagset.StringVar(&args.Kubeconfig, "kubeconfig", "",
 		"Kubeconfig to use")
 	flagset.BoolVar(&args.Oneshot, "oneshot", false,

deployment/helm/node-feature-discovery/templates/clusterrole.yaml

@@ -80,7 +80,7 @@ rules:
   - update
 {{- end }}
 
-{{- if and .Values.gc.enable .Values.gc.rbac.create (or .Values.enableNodeFeatureApi .Values.topologyUpdater.enable) }}
+{{- if and .Values.gc.enable .Values.gc.rbac.create (or .Values.featureGates.NodeFeatureApi .Values.topologyUpdater.enable) }}
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRole

deployment/helm/node-feature-discovery/templates/clusterrolebinding.yaml

@@ -33,7 +33,7 @@ subjects:
   namespace: {{ include "node-feature-discovery.namespace" .  }}
 {{- end }}
 
-{{- if and .Values.gc.enable .Values.gc.rbac.create (or .Values.enableNodeFeatureApi .Values.topologyUpdater.enable) }}
+{{- if and .Values.gc.enable .Values.gc.rbac.create (or .Values.featureGates.NodeFeatureApi .Values.topologyUpdater.enable) }}
 ---
 apiVersion: rbac.authorization.k8s.io/v1
 kind: ClusterRoleBinding

deployment/helm/node-feature-discovery/templates/master.yaml

@@ -73,9 +73,8 @@ spec:
             {{- if .Values.master.instance | empty | not }}
             - "-instance={{ .Values.master.instance }}"
             {{- end }}
-            {{- if not .Values.enableNodeFeatureApi }}
+            {{- if not .Values.featureGates.NodeFeatureApi }}
             - "-port={{ .Values.master.port | default "8080" }}"
-            - "-enable-nodefeature-api=false"
             {{- else if gt (int .Values.master.replicaCount) 1 }}
             - "-enable-leader-election"
             {{- end }}
@@ -111,6 +110,10 @@ spec:
             - "-key-file=/etc/kubernetes/node-feature-discovery/certs/tls.key"
             - "-cert-file=/etc/kubernetes/node-feature-discovery/certs/tls.crt"
             {{- end }}
+            # Go over .Values.featureGates and create a list of feature gates
+            {{- range $key, $value := .Values.featureGates }}
+            - "-feature-gates={{ $key }}={{ $value }}"
+            {{- end }}
             - "-metrics={{ .Values.master.metricsPort  | default "8081" }}"
           volumeMounts:
             {{- if .Values.tls.enable }}

deployment/helm/node-feature-discovery/templates/nfd-gc.yaml

@@ -1,4 +1,4 @@
-{{- if and .Values.gc.enable (or .Values.enableNodeFeatureApi .Values.topologyUpdater.enable) -}}
+{{- if and .Values.gc.enable (or .Values.featureGates.NodeFeatureApi .Values.topologyUpdater.enable) -}}
 apiVersion: apps/v1
 kind: Deployment
 metadata:

deployment/helm/node-feature-discovery/templates/service.yaml

@@ -1,4 +1,4 @@
-{{- if and (not .Values.enableNodeFeatureApi) .Values.master.enable }}
+{{- if and (not .Values.featureGates.NodeFeatureApi) .Values.master.enable }}
 apiVersion: v1
 kind: Service
 metadata:

deployment/helm/node-feature-discovery/templates/serviceaccount.yaml

@@ -27,7 +27,7 @@ metadata:
   {{- end }}
 {{- end }}
 
-{{- if and .Values.gc.enable .Values.gc.serviceAccount.create (or .Values.enableNodeFeatureApi .Values.topologyUpdater.enable) }}
+{{- if and .Values.gc.enable .Values.gc.serviceAccount.create (or .Values.featureGates.NodeFeatureApi .Values.topologyUpdater.enable) }}
 ---
 apiVersion: v1
 kind: ServiceAccount

deployment/helm/node-feature-discovery/templates/worker.yaml

@@ -61,15 +61,18 @@ spec:
         command:
         - "nfd-worker"
         args:
-        {{- if not .Values.enableNodeFeatureApi }}
+        {{- if not .Values.featureGates.NodeFeatureApi }}
         - "-server={{ include "node-feature-discovery.fullname" . }}-master:{{ .Values.master.service.port }}"
-        - "-enable-nodefeature-api=false"
         {{- end }}
 {{- if .Values.tls.enable }}
         - "-ca-file=/etc/kubernetes/node-feature-discovery/certs/ca.crt"
         - "-key-file=/etc/kubernetes/node-feature-discovery/certs/tls.key"
         - "-cert-file=/etc/kubernetes/node-feature-discovery/certs/tls.crt"
 {{- end }}
+        # Go over .Values.featureGates and create a list of feature gates
+        {{- range $key, $value := .Values.featureGates }}
+        - "-feature-gates={{ $key }}={{ $value }}"
+        {{- end }}
         - "-metrics={{ .Values.worker.metricsPort | default "8081"}}"
         ports:
           - name: metrics

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

@@ -10,7 +10,8 @@ nameOverride: ""
 fullnameOverride: ""
 namespaceOverride: ""
 
-enableNodeFeatureApi: true
+featureGates:
+  NodeFeatureApi: true
 
 priorityClassName: ""
 

docs/deployment/helm.md

@@ -98,7 +98,7 @@ Chart parameters are available.
 | `tls.certManager`     | bool   | false                                   | If enabled, requires [cert-manager](https://cert-manager.io/docs/) to be installed and will automatically create the required TLS certificates. **NOTE**: this parameter is related to the deprecated gRPC API and will be removed with it in a future release |
 | `tls.certManager.certManagerCertificate.issuerName` | string |           | If specified, it will use a pre-existing issuer instead for the required TLS certificates. **NOTE**: this parameter is related to the deprecated gRPC API and will be removed with it in a future release |
 | `tls.certManager.certManagerCertificate.issuerKind` | string |           | Specifies on what kind of issuer is used, can be either ClusterIssuer or Issuer (default).  Requires `tls.certManager.certManagerCertificate.issuerName` to be set.  **NOTE**: this parameter is related to the deprecated gRPC API and will be removed with it in a future release |
-| `enableNodeFeatureApi`| bool   | true                                    | Enable the [NodeFeature](../usage/custom-resources.md#nodefeature) CRD API for communicating node features. This will automatically disable the gRPC communication. **NOTE**: this parameter is related to the deprecated gRPC API and will be removed with it in a future release    |
+| `featureGate.NodeFeatureApi`| bool   | true                                    | Enable the [NodeFeature](../usage/custom-resources.md#nodefeature) CRD API for communicating node features. This will automatically disable the gRPC communication. **NOTE**: this parameter is related to the deprecated gRPC API and will be removed with it in a future release    |
 | `prometheus.enable`   | bool   | false                                   | Specifies whether to expose metrics using prometheus operator                                                                                |
 | `prometheus.labels`   | dict   | {}                                      | Specifies labels for use with the prometheus operator to control how it is selected                                                        |
 | `priorityClassName`   | string |                                         | The name of the PriorityClass to be used for the NFD pods. |

docs/reference/feature-gates.md

@@ -0,0 +1,23 @@
+---
+title: "Feature Gates"
+layout: default
+sort: 10
+---
+
+# Feature Gates
+{: .no_toc}
+
+---
+
+Feature gates are a set of key-value pairs that control the behavior of NFD.
+They are used to enable or disable certain features of NFD. 
+The feature gates are set using the `-feature-gates` command line flag or
+Helm values.featureGates. The following feature gates are available:
+
+- `NodeFeatureApi`: Enable the NodeFeature API. When enabled, NFD uses the
+  NodeFeature API to communicate feature data between NFD master and worker
+  instances. When disabled, NFD uses gRPC to communicate feature data between
+  NFD master and worker instances. The NodeFeature API is the recommended
+  method for communicating feature data between NFD master and worker instances.
+  The gRPC method is deprecated and will be removed in a future release.
+  Default: `true`

docs/reference/master-commandline-reference.md

@@ -30,6 +30,19 @@ Print usage and exit.
 
 Print version and exit.
 
+### -feature-gates
+
+The `-feature-gates` flag is used to enable or disable non GA features.
+The list of available feature gates can be found in the [feature gates
+documentation](../feature-gates.md).
+
+Example:
+
+```bash
+nfd-master -feature-gates NodeFeatureApi=false
+```
+
+
 ### -prune
 
 The `-prune` flag is a sub-command like option for cleaning up the cluster. It
@@ -163,24 +176,6 @@ nfd-master -verify-node-name -ca-file=/opt/nfd/ca.crt \
     -cert-file=/opt/nfd/master.crt -key-file=/opt/nfd/master.key
 ```
 
-### -enable-nodefeature-api
-
-> **NOTE** the gRPC API is deprecated and will be removed in a future release.
-> and this flag will be removed as well.
-
-The `-enable-nodefeature-api` flag enables/disables the
-[NodeFeature](../usage/custom-resources.md#nodefeature) CRD API for receiving
-feature requests. This will also automatically disable/enable the gRPC
-interface.
-
-Default: true
-
-Example:
-
-```bash
-nfd-master -enable-nodefeature-api=false
-```
-
 ### -enable-leader-election
 
 The `-enable-leader-election` flag enables leader election for NFD-Master.

docs/reference/worker-commandline-reference.md

@@ -30,6 +30,18 @@ Print usage and exit.
 
 Print version and exit.
 
+### -feature-gates
+
+The `-feature-gates` flag is used to enable or disable non GA features.
+The list of available feature gates can be found in the [feature gates
+documentation](../feature-gates.md).
+
+Example:
+
+```bash
+nfd-master -feature-gates NodeFeatureApi=false
+```
+
 ### -config
 
 The `-config` flag specifies the path of the nfd-worker configuration file to
@@ -210,26 +222,6 @@ Example:
 nfd-worker -label-sources=kernel,system,local
 ```
 
-### -enable-nodefeature-api
-
-> **NOTE** the gRPC API is deprecated and will be removed in a future release.
-> and this flag will be removed as well.
-
-The `-enable-nodefeature-api` flag enables/disables the
-[NodeFeature](../usage/custom-resources.md#nodefeature) CRD API
-for communicating with nfd-master. When enabled nfd-worker creates per-node
-NodeFeature objects the contain all discovered node features and the set of
-feature labels to be created. Setting the flag to false will enable
-gRPC communication to nfd-master.
-
-Default: true
-
-Example:
-
-```bash
-nfd-worker -enable-nodefeature-api=false
-```
-
 ### -metrics
 
 The `-metrics` flag specifies the port on which to expose

docs/usage/nfd-gc.md

@@ -26,5 +26,5 @@ default garbage collector interval is set to 1h which is the value when no
 
 In Helm deployments (see
 [garbage collector parameters](../deployment/helm.md#garbage-collector-parameters))
-NFD-GC will only be deployed when `enableNodeFeatureApi` or
+NFD-GC will only be deployed when `featureGates.NodeFeatureApi` or
 `topologyUpdater.enable` is set to true.

docs/usage/nfd-master.md

@@ -31,8 +31,8 @@ received from nfd-worker instances through
 [NodeFeature](custom-resources.md#nodefeature-custom-resource) objects.
 
 > **NOTE**: when gRPC (**DEPRECATED**)  is used for communicating
-> the features (by setting the flag `-enable-nodefeature-api=false` on both
-> nfd-master and nfd-worker, or via Helm values.enableNodeFeatureApi=false),
+> the features (by setting the flag `-feature-gates NodeFeatureApi=false` on both
+> nfd-master and nfd-worker, or via Helm values.featureGates.NodeFeatureApi=false),
 > (re-)labelling only happens when a request is received from nfd-worker.
 > That is, in practice rules are evaluated and labels for each node are created
 > on intervals specified by the

pkg/features/features.go

@@ -0,0 +1,29 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+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 features
+
+import (
+	utils "sigs.k8s.io/node-feature-discovery/pkg/utils"
+)
+
+const (
+	NodeFeatureAPI utils.Feature = "NodeFeatureApi"
+)
+
+var DefaultNFDFeatureGates = map[utils.Feature]utils.FeatureSpec{
+	NodeFeatureAPI: {Default: true, PreRelease: utils.Deprecated},
+}