Docs to change Container runtime (#30141)

* Docs to change Container runtime

* Updated header

* Updated header

* Few changes made according to the reviews

* Updated few headings

* Updated few markdown changes

* Reverted a unwanted changes

* Removed the double extension in the filename

* Updated

* Updated according to review

* Final Updates

* Added instructions to remove docker engine

* Minor changes

* Minor updates on heading

* Minor updates on lists

* Minor updates on line 106

* Minor updates on line 106

Author: Debanitrkl

content/en/docs/tasks/administer-cluster/migrating-from-dockershim/change-runtime-containerd.md

@@ -0,0 +1,154 @@
+---
+title: "Changing the Container Runtime on a Node from Docker Engine to containerd"
+weight: 8
+content_type: task 
+---
+
+This task outlines the steps needed to update your container runtime to containerd from Docker. It is applicable for cluster operators running Kubernetes 1.23 or earlier. Also  this covers an example scenario for migrating from dockershim to containerd and alternative container runtimes can be picked from this [page](https://kubernetes.io/docs/setup/production-environment/container-runtimes/).
+
+## {{% heading "prerequisites" %}}
+
+{{% thirdparty-content %}}
+
+Install containerd. For more information see, [containerd's installation documentation](https://containerd.io/docs/getting-started/) and for specific prerequisite follow [this](/docs/setup/production-environment/container-runtimes/#containerd).
+
+## Drain the node 
+
+```
+# replace <node-to-drain> with the name of your node you are draining
+kubectl drain <node-to-drain> --ignore-daemonsets
+```
+## Stop the Docker daemon
+
+```shell
+systemctl stop kubelet
+systemctl disable docker.service --now
+```
+
+## Install Containerd
+
+This [page](/docs/setup/production-environment/container-runtimes/#containerd) contains detailed steps to install containerd.
+
+{{< tabs name="tab-cri-containerd-installation" >}}
+{{% tab name="Linux" %}}
+
+1. Install the `containerd.io` package from the official Docker repositories. 
+Instructions for setting up the Docker repository for your respective Linux distribution and installing the `containerd.io` package can be found at 
+[Install Docker Engine](https://docs.docker.com/engine/install/#server).
+
+2. Configure containerd:
+
+   ```shell
+   sudo mkdir -p /etc/containerd
+   containerd config default | sudo tee /etc/containerd/config.toml
+   ```
+
+3. Restart containerd:
+
+   ```shell
+   sudo systemctl restart containerd
+   ```
+
+{{% /tab %}}
+{{% tab name="Windows (PowerShell)" %}}
+
+Start a Powershell session, set `$Version` to the desired version (ex: `$Version="1.4.3"`), and then run the following commands:
+
+1. Download containerd:
+
+   ```powershell
+   curl.exe -L https://github.com/containerd/containerd/releases/download/v$Version/containerd-$Version-windows-amd64.tar.gz -o containerd-windows-amd64.tar.gz
+   tar.exe xvf .\containerd-windows-amd64.tar.gz
+   ```
+
+2. Extract and configure:
+
+   ```powershell
+   Copy-Item -Path ".\bin\" -Destination "$Env:ProgramFiles\containerd" -Recurse -Force
+   cd $Env:ProgramFiles\containerd\
+   .\containerd.exe config default | Out-File config.toml -Encoding ascii
+
+   # Review the configuration. Depending on setup you may want to adjust:
+   # - the sandbox_image (Kubernetes pause image)
+   # - cni bin_dir and conf_dir locations
+   Get-Content config.toml
+
+   # (Optional - but highly recommended) Exclude containerd from Windows Defender Scans
+   Add-MpPreference -ExclusionProcess "$Env:ProgramFiles\containerd\containerd.exe"
+   ```
+
+3. Start containerd:
+
+   ```powershell
+   .\containerd.exe --register-service
+   Start-Service containerd
+   ```
+
+{{% /tab %}}
+{{< /tabs >}}
+
+## Configure the kubelet to use containerd as its container runtime
+
+Edit the file `/var/lib/kubelet/kubeadm-flags.env` and add the containerd runtime to the flags. `--container-runtime=remote` and `--container-runtime-endpoint=unix:///run/containerd/containerd.sock"`
+
+For users using kubeadm should consider the following:
+
+The `kubeadm` tool stores the CRI socket for each host as an annotation in the Node object for that host.
+
+To change it you must do the following:
+
+Execute `kubectl edit no <NODE-NAME>` on a machine that has the kubeadm `/etc/kubernetes/admin.conf` file.
+
+This will start a text editor where you can edit the Node object.
+
+To choose a text editor you can set the `KUBE_EDITOR` environment variable.
+
+- Change the value of `kubeadm.alpha.kubernetes.io/cri-socket` from `/var/run/dockershim.sock`
+   to the CRI socket path of your choice (for example `unix:///run/containerd/containerd.sock`).
+   
+   Note that new CRI socket paths must be prefixed with `unix://` ideally.
+
+- Save the changes in the text editor, which will update the Node object.
+
+## Restart the kubelet
+
+```shell
+systemctl start kubelet
+```
+
+## Verify that the node is healthy
+
+Run `kubectl get nodes -o wide` and containerd appears as the runtime for the node we just changed.
+
+## Remove Docker Engine
+
+{{% thirdparty-content %}}
+
+Finally if everything goes well remove docker
+
+{{< tabs name="tab-remove-docker-enigine" >}}
+{{% tab name="CentOS" %}}
+
+```shell
+sudo yum remove docker-ce docker-ce-cli
+```
+{{% /tab %}}
+{{% tab name="Debian" %}}
+
+```shell
+sudo apt-get purge docker-ce docker-ce-cli
+```
+{{% /tab %}}
+{{% tab name="Fedora" %}}
+
+```shell
+sudo dnf remove docker-ce docker-ce-cli
+```
+{{% /tab %}}
+{{% tab name="Ubuntu" %}}
+
+```shell
+sudo apt-get purge docker-ce docker-ce-cli
+```
+{{% /tab %}}
+{{< /tabs >}}