*   `etcd2` as a backend is deprecated and support will be removed in Kubernetes 1.13 or 1.14.

### **Auth**

*   Default controller-manager options for `--cluster-signing-cert-file` and `--cluster-signing-key-file` are deprecated and will be removed in a future release. ([#54495](https://github.com/kubernetes/kubernetes/pull/54495),[ @mikedanese](https://github.com/mikedanese))

- Added kubelet metrics to track the memory manager allocation and pinning. ([#121778](https://github.com/kubernetes/kubernetes/pull/121778), [@Tal-or](https://github.com/Tal-or))

- Fixed bug where dry run message was not printed when running `kubectl label` with `--dry-run` flag. ([#111571](https://github.com/kubernetes/kubernetes/pull/111571), [@brianpursley](https://github.com/brianpursley))

- Kubeadm: warn but do not error out on missing "ca.key" files for root CA, front-proxy CA and etcd CA, during "kubeadm join --control-plane" if the user has provided all certificates, keys and kubeconfig files which require signing with the given CA keys. ([#94988](https://github.com/kubernetes/kubernetes/pull/94988), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

### Other (Cleanup or Flake)

- The kubelet and the default docker runtime now support running ephemeral containers in the Linux process namespace of a target container. Other container runtimes must implement this feature before it will...

		* Restored the ability of kubectl running inside a pod to consume resource files specifying a different namespace than the one the pod is running in. ([#44862](https://github.com/kubernetes/kubernetes/pull/44862), [@liggitt](https://github.com/liggitt))

- Kube-apiserver: Promoted the `ExternalServiceAccountTokenSigner` feature to beta, which enabled external signing of service account tokens and fetching of public verifying keys. This was accomplished by enabling the beta `ExternalServiceAccountTokenSigner` feature gate and specifying the `--service-account-signing-endpoint` flag. The flag value could either be the path to a Unix domain socket on the filesystem, or be prefixed with @ to indicate a Unix domain...

- Made `apiextensions-apiserver` binary linking static (also affects the deb and rpm packages). ([#114226](https://github.com/kubernetes/kubernetes/pull/114226), [@saschagrunert](https://github.com/saschagrunert))

* Fixes bug finding master replicas in GCE when running multiple Kubernetes clusters. ([#58561](https://github.com/kubernetes/kubernetes/pull/58561), [@jesseshieh](https://github.com/jesseshieh))

  cluster please make sure that the nodes with version 1.6+ contains this
  label.

### kubectl
* Running `kubectl taint` (alpha in 1.5) against a 1.6 server requires upgrading kubectl to version 1.6
* Running `kubectl taint` (alpha in 1.5) against a 1.5 server requires a kubectl version of 1.5
* Running `kubectl create secret` no longer accepts passing multiple values to a single --from-literal flag using comma separation