**Who is affected?**

Only Kubernetes 1.5.0-1.5.4 installations that do all of the following:
* Enable the PodSecurityPolicy API (which is not enabled by default):
  * `--runtime-config=extensions/v1beta1/podsecuritypolicy=true`
* Enable the PodSecurityPolicy admission plugin (which is not enabled by default):
  * `--admission-control=...,PodSecurityPolicy,...`
* Use authorization to limit users' ability to use specific PodSecurityPolicy objects

- Added to `MutableFeatureGate` the ability to override the default setting of feature gates, to allow default-enabling a feature on a component-by-component basis instead of for all affected components simultaneously. ([#122647](https://github.com/kubernetes/kubernetes/pull/122647), [@benluddy](https://github.com/benluddy))

      * if the new state is "partialDisruption" or "fullDisruption" we call a user defined function that returns a new QPS to use (default 1/10 of the default rate, and the default rate respectively),
      * if the new state is "normal" we resume normal operation (go back to default limiter settings),
      * if all zones in the cluster are in "fullDisruption" state we stop all evictions.