Admission Controllers allow you to add extra options to the work of Kubernetes for changing or validating objects when making Kubernetes API requests. If the controller rejects the request, then the entire request to the API server is rejected, and an error is returned to the end user.
To enable admission controllers, you must list the names of the controllers when creating or updating a cluster. Next, kube-apiserver will be started or restarted with the
--enable-admission-plugins option and the specified access controllers.
Please note that when passing a controller that is not available for the current Kubernetes version, a corresponding error message will be returned.
To get information about the available controllers for each of the available Kubernetes versions, use an API request.