a file. ([#59666](https://github.com/kubernetes/kubernetes/pull/59666), [@mtaufen](https://github.com/mtaufen))

* [GCP kube-up.sh] Variables that were part of kube-env that were only used for kubelet flags are no longer being set, and are being replaced by the more portable mechanism of the kubelet configuration file. The individual variables in the kube-env metadata entry were never meant to be a stable interface and this release note only applies if you are depending on them. ([#60...

    * [metatada-proxy addon] Bump prometheus-to-sd v0.5.0 to pick up security fixes.

  * Kube-Proxy now defaults to an iptables-based proxy. If the --proxy-mode flag is
specified while starting kube-proxy (‘userspace’ or ‘iptables’), the flag value
will be respected. If the flag value is not specified, the kube-proxy respects
the Node object annotation: ‘net.beta.kubernetes.io/proxy-mode’. If the

* The kube-apiserver [basic audit log](https://kubernetes.io/docs/admin/audit/) can be enabled in GCE by exporting the environment variable `ENABLE_APISERVER_BASIC_AUDIT=true` before running `cluster/kube-up.sh`. This will log to `/var/log/kube-apiserver-audit.log` and use the same `logrotate` settings as `/var/log/kube-apiserver.log`. ([#41211](https://github.com/kubernetes/kubernetes/pull/41211), [@enisoc](ht...

through the built-in NodeRestriction admission plugin.

**Affected Versions**:
  - kube-apiserver v1.20.0 - v1.20.5
  - kube-apiserver v1.19.0 - v1.19.9
  - kube-apiserver <= v1.18.17

**Fixed Versions**:
  - kube-apiserver v1.21.0
  - kube-apiserver v1.20.6
  - kube-apiserver v1.19.10
  - kube-apiserver v1.18.18

This vulnerability was reported by Rogerio Bastos & Ari Lima from RedHat

* [Experiment Only] When using kube-up.sh on GCE, user could set env `KUBE_PROXY_DAEMONSET=true` to run kube-proxy as a DaemonSet. kube-proxy is run as static pods by default. ([#50705](https://github.com/kubernetes/kubernetes/pull/50705), [@MrHohn](https://github.com/MrHohn))

    * Support extra `--prune-whitelist` resources in kube-addon-manager.
    * Update kubectl to v1.10.7.
* Support extra `--prune-whitelist` resources in kube-addon-manager. ([#67743](https://github.com/kubernetes/kubernetes/pull/67743), [@Random-Liu](https://github.com/Random-Liu))

Before upgrading to Kubernetes 1.13, you must keep the following in mind:

- kube-apiserver

  - ip-mask-agent addon starts to use the label `node.kubernetes.io/masq-agent-ds-ready` instead of `beta.kubernetes.io/masq-agent-ds-ready` as its node selector.
  - kube-proxy addon starts to use the label `node.kubernetes.io/kube-proxy-ds-ready` instead of `beta.kubernetes.io/kube-proxy-ds-ready` as its node selector.

- kubeadm: Control plane images (etcd, kube-apiserver, kube-proxy, etc.) no longer use arch suffixes. Arch suffixes are kept for kube-dns only. ([#66960](https://github.com/kubernetes/kubernetes/pull/66960),...