<p>As the title says, I can't figure out how you're supposed to do this.  The pricing calculator allows for it, so I'm assuming it's possible.</p>

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

<p>1) Creating a new cluster </p>

<p>2) Creating a vm and adding it to an existing cluster, then deleting the initial node (Tried with and without the scaleset option)</p>

<p>For #1, I see no options to add a reserved instance during cluster initialization.  For #2, I see no options to add an existing vm to an existing aks cluster.</p>

<p>Anyone know how to do this?</p>

<blockquote>
  <p>After you buy an Azure Reserved Virtual Machine Instance, the reservation  discount is automatically applied to virtual machines that match the attributes and quantity of the reservation. A reservation covers the compute costs of your virtual machines. <a href="https://learn.microsoft.com/en-us/azure/billing/billing-understand-vm-reservation-charges" rel="nofollow noreferrer">Source</a></p>
</blockquote>

<p>In the <a href="https://learn.microsoft.com/en-us/azure/billing/billing-understand-vm-reservation-charges#instance-size-flexibility-setting" rel="nofollow noreferrer">documentation</a> you can see that this also applies to AKS. </p>

<p>In other words, you buy a reserved instance and after you create your AKS cluster selecting instances with the same size, the discount will be automatically applied. </p>

<blockquote>
  <p>A reservation discount applies to the base VMs that you purchase from the Azure Marketplace. </p>
</blockquote>

<p>By Marketplace you can also read AKS.</p>
