<p>When deploying AKS cluster into different availability zones (&quot;1,2,3&quot; in our case) the vm scaleset is used for default nodepool deployment (not availability set). Everything is pretty fine there, but the problem is - while using the default nodepool scaleset, it is put into 1 fault domains only, and i did not find a way to change that (despite the fact, that the vm scaleset should be deployed into 5 fault/update domains as per documentation):</p>
<p><a href="https://i.stack.imgur.com/y2hoh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/y2hoh.png" alt="enter image description here" /></a></p>
<p>Why is it so ? How to put the nodepool into default 5 fault/update domains in addition to 3 availability zones (i mean 5 fault/update domains in each of the 3 availability zones)?</p>
<p>P.S. - You can always deploy AKS cluster's nodepool into availabilitySet, and have 5 update/fault domains, but then the availability zones are not available when using the availabilitySet.</p>

<p>By reference to this doc: <a href="https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-manage-fault-domains" rel="nofollow noreferrer">Choosing the right number of fault domains for virtual machine scale set</a>, for the regions that support zonal deployment of virtual machine scale sets and this option is selected, the default value of the fault domain count is 1 for each of the zones.</p>
<p>You can also consider aligning the number of scale set fault domains with the number of Managed Disks fault domains.</p>
