# user middlewares, the same context is used.
                # This is currently not needed, only for closing files, but used to be
                # important when dependencies with yield were closed here.
                Middleware(AsyncExitStackMiddleware),
            ]
        )

        app = self.router
        for cls, args, kwargs in reversed(middleware):

## Introduction to 1.9.0

Kubernetes version 1.9 includes new features and enhancements, as well as fixes to identified issues. The release notes contain a brief overview of the important changes introduced in this release. The content is organized by Special Interest Group ([SIG](https://github.com/kubernetes/community/blob/master/sig-list.md)).

resources (category) by specifying the categories in the [CustomResourceDefinition spec](https://kubernetes.io/docs/tasks/access-kubernetes-api/extend-api-custom-resource-definitions/#categories). Example: They can be used with `kubectl get important`, where `important` is a category. ([#59561](https://github.com/kubernetes/kubernetes/pull/59561), [@nikhita](https://github.com/nikhita))

* Fixed an issue making it possible to create a situation in which two webhooks make it impossible to delete...

    * It also detects if the correct package `python-multipart` is installed instead of the incorrect `multipart` (both importable as `multipart`).

### 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`:
  - `v1alpha1` has been removed.

## Introduction to v1.8.0

Kubernetes version 1.8 includes new features and enhancements, as well as fixes to identified issues. The release notes contain a brief overview of the important changes introduced in this release. The content is organized by Special Interest Groups ([SIGs][]).

For initial installations, see the [Setup topics][] in the Kubernetes
documentation.

### SIG Scheduling
[Pod Priority and Preemption](https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/) has graduated to Beta, so it is enabled by default. Note that this involves [significant and important changes for operators](https://github.com/kubernetes/sig-release/pull/201/files). The team also worked on improved performance and reliability of the scheduler.

### SIG Storage