<p>Is it possible to specify extended resources in Kubelet configuration or would this need to be achieved using something like a daemon pod?</p>

<p>An extended resource in this context refers to this: <a href="https://kubernetes.io/docs/tasks/administer-cluster/extended-resource-node/" rel="nofollow noreferrer">https://kubernetes.io/docs/tasks/administer-cluster/extended-resource-node/</a>. This page specifies that the way to advertise these resources is to send a patch to the nodes <code>/status</code> endpoint like so:</p>

<p><code>curl --header "Content-Type: application/json-patch+json" \
--request PATCH \
--data '[{"op": "add", "path": "/status/capacity/example.com~1dongle", "value": "4"}]' \
http://localhost:8001/api/v1/nodes/&lt;your-node-name&gt;/status</code></p>

<blockquote>
  <p>Is it possible to specify extended resources in Kubelet configuration
  or would this need to be achieved using something like a daemon pod?</p>
</blockquote>

<p>No, <strong>extended resources</strong> cannot be specified just in <strong>Kubelet</strong> configuration. If you want to configure them permanently, you can use <strong><a href="https://kubernetes.io/docs/concepts/extend-kubernetes/compute-storage-net/device-plugins/" rel="nofollow noreferrer">Device Plugins</a></strong>. </p>

<blockquote>
  <p>You can deploy a device plugin as a <code>DaemonSet</code>, as a package for your
  node’s operating system, or manually.</p>
  
  <p>The canonical directory <code>/var/lib/kubelet/device-plugins</code> requires
  privileged access, so a device plugin must run in a privileged
  security context. If you’re deploying a device plugin as a <code>DaemonSet</code>,
  <code>/var/lib/kubelet/device-plugins</code> must be mounted as a Volume in the
  plugin’s PodSpec.</p>
  
  <p>If you choose the <code>DaemonSet</code> approach you can rely on Kubernetes to:
  place the device plugin’s <code>Pod</code> onto <code>Nodes</code>, to restart the daemon <code>Pod</code>
  after failure, and to help automate upgrades.</p>
</blockquote>
