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Enabling OpenShift Container Platform features using FeatureGates

Understanding FeatureGates and Technology Preview features

You can use the FeatureGate custom resource to enable Technology Preview features throughout your cluster. This allows you, for example, to enable Technology Preview features on test clusters where you can fully test them while ensuring they are disabled on production clusters.

After turning Technology Preview features on using feature gates, they cannot be turned off and cluster upgrades are prevented.

For more information about the support scope of Red Hat Technology Preview features, see https://access.redhat.com/support/offerings/techpreview/.

This allows you, for example, to ensure that Technology Preview features are off for production clusters while leaving the features on for test clusters where you can fully test them.

Features that are affected by FeatureGates

The following features are affected by FeatureGates:

FeatureGate Description Default

RotateKubeletServerCertificate

Enables the rotation of the server TLS certificate on the cluster.

True

SupportPodPidsLimit

Enables support for limiting the number of processes (PIDs) running in a pod.

True

MachineHealthCheck

Enables automatically repairing unhealthy machines in a machine pool.

True

LocalStorageCapacityIsolation

Enable the consumption of local ephemeral storage and also the sizeLimit property of an emptyDir volume.

False

You can enable these features by editing the Feature Gate Custom Resource. Turning on these features cannot be undone and prevents the ability to upgrade your cluster.

Enabling Technology Preview features using FeatureGates

You can turn Technology Preview features on and off for all nodes in the cluster by editing the FeatureGates Custom Resource, named cluster, in the openshift-config project.

The following Technology Preview features are enabled by feature gates:

  • RotateKubeletServerCertificate

  • SupportPodPidsLimit

Turning on Technology Preview features using the FeatureGate custom resource cannot be undone and prevents upgrades.
Procedure

To turn on the Technology Preview features for the entire cluster:

  1. Create the FeatureGates instance:

    1. Switch to the Administration → Custom Resource Definitions page.

    2. On the Custom Resource Definitions page, click FeatureGate.

    3. On the Custom Resource Definitions page, click the Actions Menu and select View Instances.

    4. On the Feature Gates page, click Create Feature Gates.

    5. Replace the code with following sample:

      apiVersion: config.openshift.io/v1
kind: FeatureGate
metadata:
  name: cluster
spec: {}

    6. Click Create.

  2. To turn on the Technology Preview features, change the spec parameter to:

    apiVersion: config.openshift.io/v1
kind: FeatureGate
metadata:
  name: cluster
spec:
  featureSet: TechPreviewNoUpgrade (1)
    1 Add featureSet: TechPreviewNoUpgrade to enable the Technology Preview features that are affected by FeatureGates.