- [kube-apiserver:](#kube-apiserver)
      - [kubelet:](#kubelet)
      - [kubectl:](#kubectl)
      - [client-go:](#client-go)
  - [Changes by Kind](#changes-by-kind-20)
    - [Deprecation](#deprecation)
      - [kube-apiserver:](#kube-apiserver-1)
      - [kube-controller-manager:](#kube-controller-manager)
      - [kubelet:](#kubelet-1)
      - [kube-proxy:](#kube-proxy)
      - [kubeadm:](#kubeadm)

    * "client-certificate: /var/lib/kubelet/pki/kubelet-client-current.pem" and "client-key: /var/lib/kubelet/pki/kubelet-client-current.pem", replacing the embedded client certificate and key.
* action required: kubeadm deprecates the use of the hyperkube image ([#85094](https://github.com/kubernetes/kubernetes/pull/85094), [@rosti](https://github.com/rosti))

### Other notable changes

* [alpha] Rotation of the server TLS certificate on the kubelet. See [TLS bootstrapping - approval controller](https://kubernetes.io/docs/admin/kubelet-tls-bootstrapping/#approval-controller).

* [alpha] Rotation of the client TLS certificate on the kubelet. See [TLS bootstrapping - kubelet configuration](https://kubernetes.io/docs/admin/kubelet-tls-bootstrapping/#kubelet-configuration).

* Kubelet will set extended resource capacity to zero after it restarts. If the extended resource is exported by a device plugin, its capacity will change to a valid value after the device plugin re-connects with the Kubelet. If the extended resource is exported by an external component through direct node status capacity patching, the component should repatch the field after kubelet becomes ready again. During the time gap, pods previously...

    *   Extends the gpu_device_plugin e2e_node test to verify that scheduled pods can continue to run even after a device plugin deletion and kubelet restart.
*   The NodeController no longer supports kubelet 1.2. ([#48996](https://github.com/kubernetes/kubernetes/pull/48996),[ @k82cn](https://github.com/k82cn))

### Node Components
* **Kubelet with the Docker-CRI implementation**
  * The Docker-CRI implementation is enabled by default.
  * It is not compatible with containers created by older Kubelets. It is
    recommended to drain your node before upgrade. If you choose to perform
    an in-place upgrade, the Kubelet will automatically restart all
    Kubernetes-managed containers on the node.

- kubeadm now deletes the bootstrap-kubelet.conf file after TLS bootstrap
  User relying on bootstrap-kubelet.conf should switch to kubelet.conf that contains node credentials ([#80676](https://github.com/kubernetes/kubernetes/pull/80676), [@fabriziopandini](https://github.com/fabriziopandini))

* The following deprecated flags were removed from `kubelet`:

  * `api-servers` - add apiserver addresses to the kubeconfig file instead.

  Don't use these flags. Using deprecated flags causes the kubelet to print a warning. Using a removed flag causes the kubelet to abort the startup.

- kubelet
  - The deprecated `--google-json-key` flag has been removed. Remove the `--google-json-key` flag from kubelet invocations before upgrading. ([#69354](https://github.com/kubernetes/kubernetes/pull/69354), [@yujuhong](https://github.com/yujuhong))

 ([#64792](https://github.com/kubernetes/kubernetes/pull/64792), [@luxas](https://github.com/luxas))