How do you add K8S feature gates to a shoot cluster?

Adding a Feature Gate

In order to add a feature gate, add it as enabled to the appropriate section of the shoot.yaml file:

SectionName:
    featureGates:
        SomeKubernetesFeature: true

The available sections are kubelet, kubernetes, kubeAPIServer, kubeControllerManager, kubeScheduler, and kubeProxy.

For more detals, see the example shoot.yaml file.

What is the expected downtime when updating the shoot.yaml?

No downtime is expected after executing a shoot.yaml update.