Understanding feature gates and Technology Preview features

You can use the Feature Gate 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/.

Features that are affected by FeatureGates

The following Technology Preview features included in OpenShift Container Platform:

FeatureGate Description Default

ExperimentalCriticalPodAnnotation

Enables annotating specific Pods as critical so that their scheduling is guaranteed.

True

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.

False

CSIBlockVolume

Enables external CSI drivers to implement raw block volume support.

False

LocalStorageCapacityIsolation

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

False

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

The LocalStorageCapacityIsolation cannot be enabled.

Enabling Technology Preview features using feature gates

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

Turning

Turning on Technology Preview features using the Feature Gate Custom Resource cannot be undone and prevents upgrades.

Procedure

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

  1. In the OpenShift Container Platform web sonsole, switch to the the AdministrationCustom Resource Definitions page.

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

  3. On the Custom Resource Definitions page, click ActionsView Instances.

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

  5. Add the featureSet parameter:

    apiVersion: config.openshift.io/v1
    kind: FeatureGate
    metadata:
      name: cluster
    spec:
      featureSet: "TechPreviewNoUpgrade" (1)
    1 Add the featureSet: "TechPreviewNoUpgrade" parameter.
  6. Click Save.