<p>I have a kubernetes cluster with 3 masters and 3 workers, I want to restart one of the masters to update the system of the master machine.</p>

<p>So can I just reboot the machine directly on the console with <code>reboot</code>,
or some steps need to be done before the reboot to void the risk of out of service and data loss?</p>

<p>Take a backup of the <code>ETCD</code> if it's hosting the <code>ETCD</code>. You can use the in-built command to backup the data like</p>

<pre><code>ETCDCTL_API=3 etcdctl --endpoints=https://[127.0.0.1]:2379 --cacert=/etc/kubernetes/pki/etcd/ca.crt \
     --cert=/etc/kubernetes/pki/etcd/server.crt --key=/etc/kubernetes/pki/etcd/server.key \
     snapshot save /tmp/snapshot-pre-boot.db
</code></pre>

<p>Now drain the node using</p>

<pre><code>kubectl drain &lt;master01&gt;
</code></pre>

<p>Do the System update | patches and reboot.</p>

<p>Now uncordon the node back to the cluster</p>

<pre><code>kubectl uncordon &lt;master01&gt;
</code></pre>
