## WARNING: etcd backup strongly recommended

Before updating to 1.9, you are strongly recommended to back up your etcd data. Consult the installation procedure you are using (kargo, kops, kube-up, kube-aws, kubeadm etc) for specific advice.

* **Taints**
  * You will need to use `kubectl taint` to re-create all of your taints after kubectl and the master are upgraded to 1.6. Between the time the master is upgraded to 1.6 and when you do this, your existing taints will have no effect.

volume plugin ( `kubernetes.io/cephfs`) was removed in this release and the `cephfs` volume type became non-functional. Alternative is to use CephFS CSI driver (https://github.com/ceph/ceph-csi/) in your Kubernetes Cluster. A re-deployment of your application is required to use the new driver if you were using `kubernetes.io/cephfs` volume plugin before upgrading cluster version to 1.31+. ([#124544](https://github.com/kubernetes/kubernetes/pull/124544), [@carlory](https://github.com/carlory)) [SIG...

## Changelog since v1.18.0-beta.1

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

  * If you have to use the legacy in-tree cloud providers, you can rearrange your config like the example below. If you need the `cloud-config` file (located in `{cloud-config-path}`), you can mount it into the API Server and controller-manager containers using ExtraVolumes, as in:
```

* Implemented `kubeadm upgrade plan` for checking whether you can upgrade your cluster to a newer version ([#48899](https://github.com/kubernetes/kubernetes/pull/48899), [@luxas](https://github.com/luxas))
    * Implemented `kubeadm upgrade apply` for upgrading your cluster from one version to an other

From v1.24 onwards, you will need to either use one of the other [supported runtimes](https://kubernetes.io/docs/setup/production-environment/container-runtimes/) (such as containerd or CRI-O)
or use cri-dockerd if you are relying on Docker Engine as your container runtime.
For more information about ensuring your cluster is ready for this removal, please

context errors as needed. A future release will make the `ErrWaitTimeout` error private and callers must use `Interrupted()` instead. If you are returning `ErrWaitTimeout` from your own methods, switch to creating a location specific `cause err` and pass it to the new method `wait.ErrorInterrupted(cause) error` which will ensure `Interrupted()` returns true for your loop. 
  
  The `wait.NewExponentialBackoffManager` and `wait.NewJitteringBackoffManager` functions have been marked as deprecated....

```
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
**featureGates:**
**  SupportIPVSProxyMode: true**
```

If your cluster was installed by kubeadm, you should edit the `featureGates` field in the `kubeadm-config` ConfigMap. You can do this using `kubectl -n kube-system edit cm kubeadm-config` before upgrading. For example:

kubeadm-config Before:

```
apiVersion: v1

    - [Summary API in kubelet doesn't have accelerator metrics](#summary-api-in-kubelet-doesnt-have-accelerator-metrics)
  - [Urgent Upgrade Notes](#urgent-upgrade-notes)
    - [(No, really, you MUST read this before you upgrade)](#no-really-you-must-read-this-before-you-upgrade)
  - [Changes by Kind](#changes-by-kind-14)
    - [Deprecation](#deprecation)
    - [API Change](#api-change-4)
    - [Feature](#feature-6)