* When performing a GET then PUT, the kube-apiserver must write the canonical representation of the object to etcd if the current value does not match. That allows external agents to migrate content in etcd from one API version to another, across different storage types, or across varying encryption levels. This fixes a bug introduced in 1.5 where we unintentionally stopped writing the newest data. ([#483...

* etcd3: update etcd godep to 3.0.9 to address TestWatch issues ([#32822](https://github.com/kubernetes/kubernetes/pull/32822), [@timothysc](https://github.com/timothysc))
* etcd3: update to etcd 3.0.10 ([#33393](https://github.com/kubernetes/kubernetes/pull/33393), [@timothysc](https://github.com/timothysc))

### SIG Cluster Lifecycle

  * kubeadm: The `:Etcd` struct has been refactored in the v1alpha2 API. All the options now reside under either `.Etcd.Local` or `.Etcd.External`. Automatic conversions from the v1alpha1 API are supported. ([#64066](https://github.com/kubernetes/kubernetes/pull/64066), [@luxas](https://github.com/luxas))

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all entries in the output table is included - for both certificates on disk and in kubeconfig files. ([#106923](https://github.com/kube...

* etcd version 2.2.1
  * etcd version 3.0.14 [has also been validated](https://k8s-gubernator.appspot.com/builds/kubernetes-jenkins/logs/ci-kubernetes-e2e-gce-etcd3/) but does require [specific configuration steps](https://coreos.com/blog/migrating-applications-etcd-v3.html)

## Changelog since v1.5.0-beta.3

### Other notable changes

- Fix an error when using external etcd but storing etcd certificates in the same folder with the same name used by kubeadm for local etcd certificates; for an older version of kubeadm, the workaround is to avoid file name used by kubeadm for local etcd. ([#80867](https://github.com/kubernetes/kubernetes/pull/80867), [@fabriziopandini](https://github.com/fabriziopandini))

* Fix mounting of UNIX sockets(and other special files) in subpaths ([#61480](https://github.com/kubernetes/kubernetes/pull/61480), [@gnufied](https://github.com/gnufied))
* Fix GCE etcd scripts to pass in all required parameters for the etcd migration utility to correctly perform HA upgrades and downgrades ([#61957](https://github.com/kubernetes/kubernetes/pull/61957), [@jpbetz](https://github.com/jpbetz))

- Kubeadm: when adding new control plane nodes with "kubeadm join", ensure that the etcd member addition is performed only if a given member URL does not already exist in the list of members. Similarly, on "kubeadm reset" only remove an etcd member if its ID exists. ([#127620](https://github.com/...

- Moved fluentd-elasticsearch addon images to community controlled location ([#73819](https://github.com/kubernetes/kubernetes/pull/73819), [@coffeepac](https://github.com/coffeepac))
- Removed local etcd members from the etcd cluster when `kubeadm reset` ([#74112](https://github.com/kubernetes/kubernetes/pull/74112), [@pytimer](https://github.com/pytimer))

- k8s-dns-node-cache image has been updated to v1.15.1 ([#76640](https://github.com/kubernetes/kubernetes/pull/76640), [@george-angel](https://github.com/george-angel))

### Unchanged