- A new kubelet metric `image_pull_duration_seconds` was added. The metric tracks the duration (in seconds) it takes for an image to be pulled, including the time spent in the waiting queue of image puller. The metric is broken down by bucketed image size. ([#121719](https://github.com/kubernetes/kubernetes/pull/121719), [@ruiwen-zhao](https://github.com/ruiwen-zhao))

* Ignore mirror pods with RestartPolicy == Never in restart tests ([#34462](https://github.com/kubernetes/kubernetes/pull/34462), [@yujuhong](https://github.com/yujuhong))
* Change image-puller restart policy to OnFailure ([#37070](https://github.com/kubernetes/kubernetes/pull/37070), [@gmarek](https://github.com/gmarek))

  * <strong>Simplified application deployment and management. </strong>
     * Dynamic Configuration (ConfigMap API in the core API group) enables application
configuration to be stored as a Kubernetes API object and pulled dynamically on
container startup, as an alternative to baking in command-line flags when a
container is built.
     * Turnkey Deployments (Deployment API (Beta) in the Extensions API group)

      * Added exported env vars to kubectl plugins so that plugin developers have access to global flags, namespace, the plugin descriptor and the full path to the caller binary.

  * Enhancement

    * `kubectl auth can-i` now supports non-resource URLs ([#46432](https://github.com/kubernetes/kubernetes/pull/46432), [@CaoShuFeng](https://github.com/CaoShuFeng))