title: Azure Kubernetes Service (AKS) and the primary node pool
body: <p><strong>Foreword</strong></p>
  
  <p>When you create a Kubernetes cluster on AKS you specify the type of VMs you want to use for your nodes (<code>--node-vm-size</code>). I read that you can't change this after you create the Kubernetes cluster, which would mean that you'd be scaling vertically instead of horizontally whenever you add resources.</p>
  
  <p>However, you can create different node pools in an AKS cluster that use different types of VMs for your nodes. So, I thought, if you want to "change" the type of VM that you chose initially, maybe add a new node pool and remove the old one ("nodepool1")?</p>
  
  <p>I tried that through the following steps:</p>
  
  <ul>
  <li>Create a node pool named "stda1v2" with a VM type of "Standard_A1_v2"</li>
  <li>Delete "nodepool1" (<code>az aks nodepool delete --cluster-name ... -g ... -n nodepool1</code></li>
  </ul>
  
  <p>Unfortunately I was met with <code>Primary agentpool cannot be deleted</code>.</p>
  
  <p><strong>Question</strong></p>
  
  <p>What is the purpose of the "primary agentpool" which cannot be deleted, and does it matter (a lot) what type of VM I choose when I create the AKS cluster (in a real world scenario)?</p>
  
  <p>Can I create other node pools and let the primary one live its life? Will it cause trouble in the future if I have node pools that use larger VMs for its nodes but the primary one still using "Standard_A1_v2" for example?</p>