<p>We have a K8s cluster on Azure (aks). On this cluster, we added a loadbalancer on the setup which installed an nginx-ingress controller.</p>

<p>Looking at the deployments:</p>

<pre><code>addon-http-application-routing-default-http-backend       1
addon-http-application-routing-external-dns               1 
addon-http-application-routing-nginx-ingress-controller   1
</code></pre>

<p>I see there is 1 of each running. Now I find very little information if these should be scaled (there is 1 pod each) and if they should, how?</p>

<p>I've tried running</p>

<pre><code>kubectl scale deployment addon-http-application-routing-nginx-ingress-controller --replicas=3 
</code></pre>

<p>Which temporarily scales it to 3 pods, but after a few moments, it is downscaled again.</p>

<p>So again, are these supposed to be scaled? Why? How?</p>

<p><strong>EDIT</strong></p>

<p>For those that missed it like I did: The AKS addon-http-application is <strong>not</strong> ready for production, it is there to quickly set you up and start experimenting. Which is why I wasn't able to scale it properly. </p>

<p><a href="https://learn.microsoft.com/en-us/azure/aks/http-application-routing" rel="nofollow noreferrer">Read more</a></p>

<p>That's generally the way how you do it:</p>

<pre><code>$ kubectl scale deployment addon-http-application-routing-nginx-ingress-controller --replicas=3
</code></pre>

<p>However, I suspect you have an <a href="https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/" rel="nofollow noreferrer">HPA</a> configured which will scale up/down depending on the load or some metrics and has the <code>minReplicas</code> spec set to <code>1</code>. You can check with:</p>

<pre><code>$ kubectl get hpa
$ kubectl describe hpa &lt;hpa-name&gt;
</code></pre>

<p>If that's the case you can scale up by just patching the HPA:</p>

<pre><code>$ kubectl patch hpa &lt;hpa-name&gt; -p '{"spec": {"minReplicas": 3}}'
</code></pre>

<p>or edit it manually:</p>

<pre><code>$ kubectl edit hpa &lt;hpa-name&gt;
</code></pre>

<p>More information on HPAs <a href="https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/" rel="nofollow noreferrer">here</a>.</p>

<p>And yes, the ingress controllers are supposed to be scaled up and down depending on the load.</p>
