- To enhance usability and developer experience, CRD validation rules now support direct use of (CEL) reserved keywords as field names in object validation expressions.

## Changes by Kind

### Bug or Regression

- Fix a bug when the hostname label of a node does not match the node name, pods bound to a PV with nodeAffinity using the hostname may be scheduled to the wrong node or experience scheduling failures. ([#127584](https://github.com/kubernetes/kubernetes/pull/127584), [@AxeZhan](https://github.com/AxeZhan)) [SIG Scheduling and Storage]

### SIG-cluster-lifecycle

In 1.12, SIG Cluster lifecycle has focused on improving the user experience in kubeadm, by fixing a number of bugs and adding some new important features.

Here is a list of some of the changes that have been made to kubeadm:

- Kubeadm internal config has been promoted to `v1alpha3`:

### SIG Cluster Lifecycle

* `federation/deploy/deploy.sh` was an interim solution introduced in Kubernetes v1.4 to simplify the federation control plane deployment experience. Now that we have `kubefed`, we are deprecating `deploy.sh` scripts. ([#38902](https://github.com/kubernetes/kubernetes/pull/38902), [@madhusudancs](https://github.com/madhusudancs))


### Cluster Provisioning Scripts

- Added the `DetectCacheInconsistency` feature gate, allowing the API server to periodically verify consistency between its `cache` and `etcd`. Detected inconsistencies reported...

- If a conflict occurs when creating an object with `generateName`, the server now returns an "AlreadyExists" error with a retry option. ([#1...

### Deprecation

- Aborting the drain command in a list of nodes will be deprecated. The new behavior will make the drain command go through all nodes even if one or more nodes failed during the drain. For now, users can try such experience by enabling --ignore-errors flag. ([#98203](https://github.com/kubernetes/kubernetes/pull/98203), [@yuzhiquan](https://github.com/yuzhiquan))

For 1.13 SIG Cluster Lifecycle is pleased to announce the long awaited promotion of kubeadm to stable GA, and the promotion of kubeadm’s configuration API to `v1beta1`.
In this release the SIG again focused on further improving the user experience on cluster creation and also fixing a number of bugs and other assorted improvements.

Some notable changes in kubeadm since Kubernetes 1.12:

This release includes a change to [kubectl get and describe to work better with extensions](https://github.com/kubernetes/enhancements/issues/515), as the server, rather than the client, returns this information for a smoother user experience.

### Network