- `kubeadm alpha certs renew` and `kubeadm upgrade` now supports renewal of certificates embedded in KubeConfig files managed by kubeadm; this does not apply to certificates signed by external CAs.  ([#77180](https://github.com/kubernetes/kubernetes/pull/77180), [@fabriziopandini](https://github.com/fabriziopandini))

version. ([#58973](https://github.com/kubernetes/kubernetes/pull/58973), [@verb](https://github.com/verb))

* The default Flexvolume plugin directory for COS images on GCE has changed to `/home/kubernetes/flexvolume`, rather than `/etc/srv/kubernetes/kubelet-plugins/volume/exec`. Existing Flexvolume installations in clusters using COS images must be moved to the new directory, and installation processes must be updated with the new path. ([#58171](https://github.com/kubernetes/kubernetes/pull/58171),...

- Add annotation to preserve floating IP after service delete.
- Add conformance testing to stable and development branches.
- Add support support to Manilla for trustee authentication and supplying custom CAs.
- Add and update documentation.
- Add support to Manilla for provisioning existing shares.
- Add cluster name to load balancer description
- Add synchronization between Kubernetes and Keystone projects

- GCE: bumped COS image version to `cos-beta-73-11647-64-0` ([#75149](https://github.com/kubernetes/kubernetes/pull/75149), [@yguo0905](https://github.com/yguo0905))

- Update to Ingress-GCE v1.6.1 ([#84018](https://github.com/kubernetes/kubernetes/pull/84018), [@rramkumar1](https://github.com/rramkumar1))
- Kubeadm: enhance certs check-expiration to show the expiration info of related CAs ([#83932](https://github.com/kubernetes/kubernetes/pull/83932), [@SataQiu](https://github.com/SataQiu))

- Changed core_pattern on COS nodes to be an absolute path. ([#86329](https://github.com/kubernetes/kubernetes/pull/86329), [@mml](https://github.com/mml)) [SIG Cluster Lifecycle and Node]

- Kube-apiserver: regular expressions specified with the `--cors-allowed-origins` option are now validated to match the entire `hostname` inside the `Origin` header of the request and 
  must contain '^' or the '//' prefix to anchor to the start, and '$' or the port separator ':' to anchor to 

* Fix 'kubectl cp' with no arguments causes a panic ([#65482](https://github.com/kubernetes/kubernetes/pull/65482), [@wgliang](https://github.com/wgliang))
* On COS, NPD creates a node condition for frequent occurrences of unregister_netdevice ([#65342](https://github.com/kubernetes/kubernetes/pull/65342), [@dashpole](https://github.com/dashpole))