* Fixes bugs that make apiserver panic when aggregating valid but not well formed OpenAPI spec ([#63635](https://github.com/kubernetes/kubernetes/pull/63635), [@roycaihw](https://github.com/roycaihw))

- Fixed `kube-proxy` panicking on exit when the `Node` object changed its `PodCIDR`. ([#120375](https://github.com/kubernetes/kubernetes/pull/120375), [@pegasas](https://github.com/pegasas))
- Fixed bugs in handling of server-side apply, create, and update API requests for objects containing duplicate items in keyed lists.

In this release the SIG again focused on further improving the user experience on cluster creation and also fixing a number of bugs and other assorted improvements.

Some notable changes in kubeadm since Kubernetes 1.12:

    * handle gracefully problem when kubelet reports duplicated stats for the same container (see [#47853](https://github.com/kubernetes/kubernetes/pull/47853)) on Heapster side
    * fixed bugs and improved performance in Stackdriver Sink

  returns `nil`. (It now returns a pointer to a zero-valued object, like the real
  clients do.) This will break some downstream unit tests that were testing
  `result == nil` rather than `err != nil`, and in some cases may expose bugs

* [fluentd-gcp addon] Use the logging agent's node name as the metadata agent URL. ([#63353](https://github.com/kubernetes/kubernetes/pull/63353), [@bmoyles0117](https://github.com/bmoyles0117))
* Fixes bugs that make apiserver panic when aggregating valid but not well formed OpenAPI spec ([#63627](https://github.com/kubernetes/kubernetes/pull/63627), [@roycaihw](https://github.com/roycaihw))

### Bug or Regression

- Disable aufs module for gce clusters ([#103831](https://github.com/kubernetes/kubernetes/pull/103831), [@lizhuqi](https://github.com/lizhuqi)) [SIG Cloud Provider]

    * overlay2 driver not fully supported
    * live-restore not fully supported
    * no shared pid namespace support
  * Docker version 1.11.2 known issues
    * Kernel crash with Aufs storage driver on Debian Jessie ([#27885](https://github.com/kubernetes/kubernetes/issues/27885))
      which can be identified by the [node problem detector](http://kubernetes.io/docs/admin/node-problem/)

* Add ipset and udevadm to the hyperkube base image. ([#61357](https://github.com/kubernetes/kubernetes/pull/61357), [@rphillips](https://github.com/rphillips))
* Fixes bugs that make apiserver panic when aggregating valid but not well formed OpenAPI spec ([#63626](https://github.com/kubernetes/kubernetes/pull/63626), [@roycaihw](https://github.com/roycaihw))

- Disable aufs module for gce clusters. ([#103831](https://github.com/kubernetes/kubernetes/pull/103831), [@lizhuqi](https://github.com/lizhuqi))