- Kubeadm: `kubeadm upgrade node` now supports `addon` and `post-upgrade` phases. User can use `kubeadm upgrade node phase addon` to execute the addon upgrade, or use `kubeadm upgrade node --skip-phases addon` to skip the addon upgrade. Currently, the `post-upgrade` phase is no-op, and it is mainly used to handle some release specific post-upgrade tasks. ([#127242](https://github.com/k...

* Update cluster-proportional-autoscaler, etcd-empty-dir-cleanup, fluentd-gcp, and kube-addon-manager addons with refreshed base images containing fixes for CVE-2015-8271, CVE-2016-7543, CVE-2016-9841, CVE-2016-9843, CVE-2017-1000366, CVE-2017-2616, and CVE-2017-7507. ([#48011](https://github.com/kubernetes/kubernetes/pull/48011), [@ixdy](https://github.com/ixdy))...

* Impersonate user extra ([#30881](https://github.com/kubernetes/kubernetes/pull/30881), [@deads2k](https://github.com/deads2k))
* DNS, Heapster and UI are critical addons ([#30995](https://github.com/kubernetes/kubernetes/pull/30995), [@piosz](https://github.com/piosz))
* AWS: Support HTTP->HTTP mode for ELB ([#30563](https://github.com/kubernetes/kubernetes/pull/30563), [@knarz](https://github.com/knarz))