Rebooting bare metal nodes

Introduction#

If you want to reboot a bare metal server that is registered as a node in your cluster (which should already be set up per the Hetzner account preparation guide), the easiest way is to reprovision it.

This can be done just by deleting the Machine object associated with the bare metal node.

However, in some cases it might be useful to reboot the machine in-place, such as when the local disk contains data which would require too much time to re-sync.

This guide will explain how you can do that.

Step 1: Set the paused annotation#

In the Autopilot cluster, set the paused annotation for the machine:

		$ kubectl annotate machine your-cluster-md-abc-xyz-ijk cluster.x-k8s.io/paused=true
	

Double-check that you don't have a typo in the annotation. Otherwise, the node will get flagged as not functional and the machine will get reprovisioned.

Step 2: Drain the node#

In your workload cluster, drain the node:

		$ kubectl drain bm-your-cluster-12345678 --ignore-daemonsets
	

And wait until all the pods are terminated. You can check with this command:

		$ kubectl get pods --all-namespaces --field-selector spec.nodeName=bm-your-cluster-12345678
	

Step 3: Reboot the server#

Now, you can SSH into the server, and perform any needed maintenance tasks.

If you are unsure how to do that, refer to the How to SSH into nodes guide.

For rebooting it, type this in the server shell:

		$ reboot
	

Step 4: Add the node back#

First, uncordon the node in your workload cluster:

		$ kubectl uncordon bm-your-cluster-12345678
	

And, in the Autopilot cluster, remove the pause annotation:

		$ kubectl annotate machine your-cluster-md-abc-xyz-ijk cluster.x-k8s.io/paused-
	

Now the node is a functional member of the cluster again.