1. If this is your first time, please read our contributor guidelines: https://git.k8s.io/community/contributors/guide/first-contribution.md#your-first-contribution and developer guide https://git.k8s.io/community/contributors/devel/development.md#development-guide

The [Kubernetes community repo](https://github.com/kubernetes/community) contains information about how to get started, how the community organizes, and more.

## Sign the CLA

## External Dependencies

Continuous integration builds use Docker versions 1.11.2, 1.12.6, 1.13.1,
and 17.03.2. These versions were validated on Kubernetes 1.8. However,
consult an appropriate installation or upgrade guide before deciding what
versions of Docker to use.

- Docker 1.13.1 and 17.03.2

    - Shared PID namespace, live-restore, and overlay2 were validated.

    - **Known issues**

of selectors to accommodate both [equality-based selectors](http://kubernetes.io/docs/user-guide/labels/#equality-based-requirement) supported by ReplicationControllers and [set-based selectors](http://kubernetes.io/docs/user-guide/labels/#set-based-requirement) supported by Deployments and ReplicaSets.
  * “kubectl run” now produces Deployments (instead of ReplicationControllers) and
Jobs (instead of Pods) by default.

## Major themes

Kubernetes is developed by community members whose work is organized into
[Special Interest Groups](https://github.com/kubernetes/community/blob/master/sig-list.md), which provide the themes that guide their work. For the 1.9 release, these themes included:

### API Machinery

Extensibility. SIG API Machinery added a new class of admission control webhooks (mutating), and brought the admission control webhooks to beta.

  - [beta] Server-side garbage collection is enabled by default. See [user-guide](http://kubernetes.io/docs/user-guide/garbage-collection/)
- **Apps**
  - [alpha] Introducing 'ScheduledJobs', which allow running time based Jobs, namely once at a specified time or repeatedly at specified point in time. ([docs](http://kubernetes.io/docs/user-guide/scheduled-jobs/)) ([kubernetes/features#19](https://github.com/kubernetes/enhancements/issues/19))

Continuous integration builds have used the following versions of external dependencies, however, this is not a strong recommendation and users should consult an appropriate installation or upgrade guide before deciding what versions of etcd, docker or rkt to use.

* Docker versions 1.10.3, 1.11.2, 1.12.6 have been validated

    * Docker version 1.12.6 known issues

## Urgent Upgrade Notes 

### (No, really, you MUST read this before you upgrade)

- Deprecated beta APIs scheduled for removal in `v1.26` are no longer served. See https://kubernetes.io/docs/reference/using-api/deprecation-guide/#v1-26 for more information. ([#111973](https://github.com/kubernetes/kubernetes/pull/111973), [@liggitt](https://github.com/liggitt))

* kubeadm: add a preflight check that throws a warning if the cgroup driver for Docker on Linux is not "systemd" as per the k8s.io CRI installation guide. ([#73837](https://github.com/kubernetes/kubernetes/pull/73837), [@neolit123](https://github.com/neolit123))

### Deployment
* **[beta]** Deployments that cannot make progress in rolling out the newest version will now indicate via the API they are blocked ([docs](https://kubernetes.io/docs/user-guide/deployments/#deployment-status))

### Federation