- Add `container_sockets`, `container_threads`, and `container_threads_max` metrics ([#81972](https://github.com/kubernetes/kubernetes/pull/81972), [@dashpole](https://github.com/dashpole))

### Container Images

All container images are available as manifest lists and support the described
architectures. It is also possible to pull a specific architecture directly by
adding the "-$ARCH" suffix  to the container image name.
name | architectures
---- | -------------

- github.com/containerd/cgroups: [0dbf7f0](https://github.com/containerd/cgroups/tree/0dbf7f0)
- github.com/containerd/continuity: [aaeac12](https://github.com/containerd/continuity/tree/aaeac12)
- github.com/containerd/fifo: [a9fb20d](https://github.com/containerd/fifo/tree/a9fb20d)
- github.com/containerd/go-runc: [5a6d9f3](https://github.com/containerd/go-runc/tree/5a6d9f3)

    * Old behavior:
      * environment variables explicitly whitelisted via --docker-env-metadata-whitelist were exported as `container_env_*=*`. Default is zero so by default non were exported
      * all docker labels were exported as `container_label_*=*`
    * New behavior:
      * Only `container_name`, `pod_name`, `namespace`, `id`, `image`, and `name` labels are exposed

## Changes since v1.3.0-beta.1

### Experimental Features

* Init containers enable pod authors to perform tasks before their normal containers start. Each init container is started in order, and failing containers will prevent the application from starting. ([#23666](https://github.com/kubernetes/kubernetes/pull/23666), [@smarterclayton](https://github.com/smarterclayton))

= vendor/github.com/container-storage-interface/spec licensed under: =

                                 Apache License
                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,

- Any Prometheus queries that match `pod_name` and `container_name` labels (e.g. cadvisor or kubelet probe metrics) should be updated to use `pod` and `container` instead. `pod_name` and `container_name` labels will be present alongside `pod` and `container` labels for one transitional release and removed in the future.

* Bump GCE ContainerVM
  * to container-vm-v20161208 ([release notes](https://cloud.google.com/compute/docs/containers/container_vms#changelog)) ([#38432](https://github.com/kubernetes/kubernetes/pull/38432), [@timstclair](https://github.com/timstclair))

* [alpha] Adds support of container metrics in CRI ([docs PR](https://github.com/kubernetes/community/pull/742)) ([kubernetes/features#290](https://github.com/kubernetes/enhancements/issues/290))

* Support starting Kubernetes on GCE using containerd in COS and Ubuntu with `KUBE_CONTAINER_RUNTIME=containerd`. ([#77889](https://github.com/kubernetes/kubernetes/pull/77889), [@Random-Liu](https://github.com/Random-Liu))