* Federation
  * federation api group is now **beta**
  * Services from all federated clusters are now registered in Cloud DNS (AWS and GCP).
* Stateful Apps:
  * **alpha** PetSets manage stateful apps
  * **alpha** Init containers provide one-time setup for stateful containers
* Updating:
  * Retry Pod/RC updates in kubectl rolling-update.
  * Stop 'kubectl drain' deleting pods with local storage.

* **Other objects**: no changes unless you explicitly request orphaning.

## Action Required Before Upgrading

- If you are using Kubernetes to manage `docker` containers, please be aware Kubernetes has been validated to work with docker 1.9.1, docker 1.11.2 (#23397), and docker 1.12.0 (#28698)

#### DaemonSet
* [beta] DaemonSet supports history and rollback. See [Performing a Rollback on a DaemonSet](https://kubernetes.io/docs/tasks/manage-daemon/rollback-daemon-set/).

#### Deployments

- Graduated the `MultiCIDRServiceAllocator` feature gate to stable, and the `DisableAllocatorDualWrite` feature gate to beta (disabled by default).
**Action required** for Kubernetes cluster administrators and for distributions that manage the cluster Service CIDR.
Kubernetes now allows users to define the cluster Service CIDR via an API object: ServiceCIDR.

- Updated the control plane's trust anchor publisher to create and manage a new ClusterTrustBundle object, associated with the `kubernetes.io/kube-apiserver-serving` X.509 certificate signer. This ClusterTrustBundle contains a PEM bundle in its payload that you can use to verify kube-apiserver serving certificates. ([#...

* Fixed API server panic during concurrent GET or LIST requests with non-empty `resourceVersion`. ([#65092](https://github.com/kubernetes/kubernetes/pull/65092), [@sttts](https://github.com/sttts))
* Properly manage security groups for loadbalancer services on OpenStack. ([#65373](https://github.com/kubernetes/kubernetes/pull/65373), [@multi-io](https://github.com/multi-io))

Besides the above new features, support for Azure Virtual Machine Scale Sets (VMSS) and Cluster-Autoscaler is now stable and considered GA:

- Azure virtual machine scale sets (VMSS) allow you to create and manage identical load balanced VMs that automatically increase or decrease based on demand or a set schedule.

### Serverside Apply - Beta 2

Server-side Apply was promoted to Beta in 1.16, but is now introducing a second Beta in 1.18. This new version will track and manage changes to fields of all new Kubernetes objects, allowing you to know what changed your resources and when.

### Extending Ingress with and replacing a deprecated annotation with IngressClass

* add external resource group support for azure disk ([#64427](https://github.com/kubernetes/kubernetes/pull/64427), [@andyzhangx](https://github.com/andyzhangx))
* Properly manage security groups for loadbalancer services on OpenStack. ([#65373](https://github.com/kubernetes/kubernetes/pull/65373), [@multi-io](https://github.com/multi-io))

- Allow kubectl to manage resources by filename patterns without the shell expanding it first ([#102265](https://github.com/kubernetes/kubernetes/pull/102265), [@danielrodriguez](https://github.com/danielrodriguez))