* Unmount operation should not fail if volume is already unmounted ([#38547](https://github.com/kubernetes/kubernetes/pull/38547), [@rkouj](https://github.com/rkouj))
* Updates base image used for `kube-addon-manager` to latest `python:2.7-slim` and embedded `kubectl` to `v1.3.10`. No functionality changes expected. ([#42842](https://github.com/kubernetes/kubernetes/pull/42842), [@ixdy](https://github.com/ixdy))

* Disable anonymous auth on kubelet ([#41919](https://github.com/kubernetes/kubernetes/pull/41919), [@Cynerva](https://github.com/Cynerva))
* Fix shebangs in charm actions to use python3 ([#42058](https://github.com/kubernetes/kubernetes/pull/42058), [@Cynerva](https://github.com/Cynerva))

- **API Machinery**
  - [beta] `kube-apiserver` support for the OpenAPI spec is moving from alpha to beta. The first [non-go client](https://github.com/kubernetes-incubator/client-python) is based on it ([kubernetes/features#53](https://github.com/kubernetes/enhancements/issues/53))
- **Apps**