Add Documentation for Kubectl debug node command (#35300)

* Add Documentation for Kubectl debug node command

* Add documentation for kubectl debug node command

* Refactor changes

* Add information to find logs

* Apply suggestions from code review

Co-authored-by: Tim Bannister <tim@scalefactory.com>
Co-authored-by: Shannon Kularathna <ax3shannonkularathna@gmail.com>

* Refactor wordings based on reviews

* Correct the link to kubectl-node-debug on index page

* Minor refactor(Review comments)

* Address review comments

* Minor refactor as per suggestions from code review

Co-authored-by: Rey Lejano <rlejano@gmail.com>

* Use an example for pod deletion

* Address review comments

* Address review comments

Co-authored-by: Tim Bannister <tim@scalefactory.com>
Co-authored-by: Shannon Kularathna <ax3shannonkularathna@gmail.com>
Co-authored-by: Rey Lejano <rlejano@gmail.com>

content/en/docs/tasks/debug/debug-cluster/_index.md

@@ -323,6 +323,7 @@ This is an incomplete list of things that could go wrong, and how to adjust your
   [monitoring resource usage](/docs/tasks/debug/debug-cluster/resource-usage-monitoring/)
 * Use Node Problem Detector to
   [monitor node health](/docs/tasks/debug/debug-cluster/monitor-node-health/)
+* Use `kubectl debug node` to [debug Kubernetes nodes](/docs/tasks/debug/debug-cluster/kubectl-node-debug) 
 * Use `crictl` to [debug Kubernetes nodes](/docs/tasks/debug/debug-cluster/crictl/)
 * Get more information about [Kubernetes auditing](/docs/tasks/debug/debug-cluster/audit/)
 * Use `telepresence` to [develop and debug services locally](/docs/tasks/debug/debug-cluster/local-debugging/)

content/en/docs/tasks/debug/debug-cluster/kubectl-node-debug.md

@@ -0,0 +1,109 @@
+---
+title: Debugging Kubernetes Nodes With Kubectl
+content_type: task
+min-kubernetes-server-version: 1.20
+---
+
+<!-- overview -->
+This page shows how to debug a [node](/docs/concepts/architecture/nodes/)
+running on the Kubernetes cluster using `kubectl debug` command.
+
+## {{% heading "prerequisites" %}}
+
+
+{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
+
+You need to have permission to create Pods and to assign those new Pods to arbitrary nodes.
+You also need to be authorized to create Pods that access filesystems from the host.
+
+
+<!-- steps -->
+
+## Debugging a Node using `kubectl debug node`
+
+Use the `kubectl debug node` command to deploy a Pod to a Node that you want to troubleshoot.
+This command is helpful in scenarios where you can't access your Node by using an SSH connection.
+When the Pod is created, the Pod opens an interactive shell on the Node.
+To create an interactive shell on a Node named “mynode”, run:
+
+```shell
+kubectl debug node/mynode -it --image=ubuntu
+```
+
+```console
+Creating debugging pod node-debugger-mynode-pdx84 with container debugger on node mynode.
+If you don't see a command prompt, try pressing enter.
+root@mynode:/#
+```
+
+The debug command helps to gather information and troubleshoot issues. Commands 
+that you might use include `ip`, `ifconfig`, `nc`, `ping`, and `ps` and so on. You can also
+install other tools, such as `mtr`, `tcpdump`, and `curl`, from the respective package manager.
+
+{{< note >}}
+
+The debug commands may differ based on the image the debugging pod is using and
+these commands might need to be installed.
+
+{{< /note >}}
+
+The debugging Pod can access the root filesystem of the Node, mounted at `/host` in the Pod.
+If you run your kubelet in a filesystem namespace,
+the debugging Pod sees the root for that namespace, not for the entire node. For a typical Linux node,
+you can look at the following paths to find relevant logs:
+
+`/host/var/log/kubelet.log`
+: Logs from the `kubelet`, responsible for running containers on the node.
+
+`/host/var/log/kube-proxy.log`
+: Logs from `kube-proxy`, which is responsible for directing traffic to Service endpoints.
+
+`/host/var/log/containerd.log`
+: Logs from the `containerd` process running on the node.
+
+`/host/var/log/syslog`
+: Shows general messages and information regarding the system.
+
+`/host/var/log/kern.log`
+: Shows kernel logs.
+
+When creating a debugging session on a Node, keep in mind that:
+
+* `kubectl debug` automatically generates the name of the new pod, based on
+  the name of the node.
+* The root filesystem of the Node will be mounted at `/host`.
+* Although the container runs in the host IPC, Network, and PID namespaces,
+  the pod isn't privileged. This means that reading some process information might fail
+  because access to that information is restricted to superusers. For example, `chroot /host` will fail.
+  If you need a privileged pod, create it manually.
+
+## {{% heading "cleanup" %}}
+
+When you finish using the debugging Pod, delete it:
+
+```shell
+kubectl get pods
+```
+
+```none
+NAME                          READY   STATUS       RESTARTS   AGE
+node-debugger-mynode-pdx84    0/1     Completed    0          8m1s
+```	
+
+```shell
+# Change the pod name accordingly
+kubectl delete pod node-debugger-mynode-pdx84 --now
+```	
+
+```none
+pod "node-debugger-mynode-pdx84" deleted
+```
+
+{{< note >}}
+
+The `kubectl debug node` command won't work if the Node is down (disconnected
+from the network, or kubelet dies and won't restart, etc.).
+Check [debugging a down/unreachable node ](/docs/tasks/debug/debug-cluster/#example-debugging-a-down-unreachable-node)
+in that case.
+
+{{< /note >}}