Enable Or Disable Feature Gates

This page shows how to enable or disable feature gates to control specific Kubernetes features in your cluster. Enabling feature gates allows you to test and use Alpha or Beta features before they become generally available.

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

• iximiuz Labs
• Killercoda
• KodeKloud
• Play with Kubernetes

You also need:

• Administrative access to your cluster
• Knowledge of which feature gate you want to enable (see the Feature Gates reference)

Understand feature gate maturity

Before enabling a feature gate, check the Feature Gates reference for the feature's maturity level:

• Alpha: Disabled by default, may be buggy. Use only in test clusters.
• Beta: Usually enabled by default, well-tested.
• GA: Always enabled by default; can sometimes be disabled for one release after GA.

Identify which components need the feature gate

Different feature gates affect different Kubernetes components:

• Some features require enabling the gate on multiple components (e.g., API server and controller manager)
• Other features only need the gate on a single component (e.g., only kubelet)

The Feature Gates reference typically indicates which components are affected by each gate. All Kubernetes components share the same feature gate definitions, so all gates appear in help output, but only relevant gates affect each component's behavior.

Configuration

During cluster initialization

Create a configuration file to enable feature gates across relevant components:

apiVersion: kubeadm.k8s.io/v1beta4
kind: ClusterConfiguration
apiServer:
  extraArgs:
    feature-gates: "FeatureName=true"
controllerManager:
  extraArgs:
    feature-gates: "FeatureName=true"
scheduler:
  extraArgs:
    feature-gates: "FeatureName=true"
---
apiVersion: kubelet.config.k8s.io/v1beta1
kind: KubeletConfiguration
featureGates:
  FeatureName: true

Initialize the cluster:

kubeadm init --config kubeadm-config.yaml

On an existing cluster

For kubeadm clusters, feature gate configuration can be set in several locations including manifest files, configuration files, and kubeadm configuration.

Edit control plane component manifests in /etc/kubernetes/manifests/:

1. For kube-apiserver, kube-controller-manager, or kube-scheduler, add the flag to the command:

   spec:
     containers:
     - command:
       - kube-apiserver
       - --feature-gates=FeatureName=true
       # ... other flags
   

   Save the file. The pod restarts automatically.

2. For kubelet, edit /var/lib/kubelet/config.yaml:

   apiVersion: kubelet.config.k8s.io/v1beta1
   kind: KubeletConfiguration
   featureGates:
     FeatureName: true
   

   Restart kubelet:

   sudo systemctl restart kubelet
   

3. For kube-proxy, edit the ConfigMap:

   kubectl -n kube-system edit configmap kube-proxy
   

   Add feature gates to the configuration:

   featureGates:
     FeatureName: true
   

   Restart the DaemonSet:

   kubectl -n kube-system rollout restart daemonset kube-proxy
   

Configure multiple feature gates

Use comma-separated lists for command-line flags:

--feature-gates=FeatureA=true,FeatureB=false,FeatureC=true

For components that support configuration files (kubelet, kube-proxy):

featureGates:
  FeatureA: true
  FeatureB: false
  FeatureC: true

Verify feature gate configuration

After configuring, verify the feature gates are active. The following methods apply to kubeadm clusters where control plane components run as static pods.

Check control plane component manifests

View the feature gates configured in the static pod manifest:

kubectl -n kube-system get pod kube-apiserver-<node-name> -o yaml | grep feature-gates

Check kubelet configuration

Use the kubelet's configz endpoint:

kubectl proxy --port=8001 &
curl -sSL "http://localhost:8001/api/v1/nodes/<node-name>/proxy/configz" | grep featureGates -A 5

Or check the configuration file directly on the node:

cat /var/lib/kubelet/config.yaml | grep -A 10 featureGates

Check via metrics endpoint

Feature gate status is exposed in Prometheus-style metrics by Kubernetes components (available in Kubernetes 1.26+). Query the metrics endpoint to verify which feature gates are enabled:

kubectl get --raw /metrics | grep kubernetes_feature_enabled

To check a specific feature gate:

kubectl get --raw /metrics | grep kubernetes_feature_enabled | grep FeatureName

The metric shows 1 for enabled gates and 0 for disabled gates.

Check via /flagz endpoint

If you have access to a component's debugging endpoints, and the ComponentFlagz feature gate is enabled for that component, you can inspect the command-line flags that were used to start the component by visiting the /flagz endpoint. Feature gates configured using command-line flags appear in this output.

The /flagz endpoint is part of Kubernetes z-pages, which provide human-readable runtime debugging information for core components.

For more information, see the z-pages documentation.

Understanding component-specific requirements

Some examples of component-specific feature gates:

• API server-focused: Features like StructuredAuthenticationConfiguration primarily affect kube-apiserver
• Kubelet-focused: Features like GracefulNodeShutdown primarily affect kubelet
• Multiple components: Some features require coordination between components

Always test feature gates in non-production environments first. Alpha features may be removed without notice.

What's next

• Read the Feature Gates reference
• Learn about Feature Stages
• Review kubeadm configuration