Exam AZ-103 topic 16 question 6 discussion

1. Stop VM1, VM2, VM3 2. Resize VM1 2. Start VM1, VM2, VM3

“If your VM(s) are deployed using the Resource Manager (ARM) deployment model and you need to change to a size which requires different hardware then you can resize VMs by first stopping your VM, selecting a new VM size and then restarting the VM. If the VM you wish to resize is part of an availability set, then you must stop all VMs in the availability set before changing the size of any VM in the availability set. The reason all VMs in the availability set must be stopped before performing the resize operation to a size that requires different hardware is that all running VMs in the availability set must be using the same physical hardware cluster. Therefore, if a change of physical hardware cluster is required to change the VM size then all VMs must be first stopped and then restarted one-by-one to a different physical hardware clusters.”

Same question here: https://www.examtopics.com/exams/microsoft/az-103/view/14/

Cause A request to resize a VM or add a VM to an existing availability set must be tried at the original cluster that hosts the existing availability set. The requested VM size is supported by the cluster, but the cluster may not currently have sufficient capacity. Workaround If the VM can be part of a different availability set, create a VM in a different availability set (in the same region). This new VM can then be added to the same virtual network. Stop (deallocate) all VMs in the same availability set, then restart each one. To stop: Click Resource groups > [your resource group] > Resources > [your availability set] > Virtual Machines > [your virtual machine] > Stop. After all VMs stop, select the first VM, and then click Start. This step makes sure that a new allocation attempt is run and that a new cluster can be selected that has sufficient capacity.

You only need to stop all VM's in an availability set if the size is not supported on the current hardware cluster. Otherwise you can resize without stopping all VM's in the availability set. This document explains it and provides the powershell for each situation including how to check if the size is available: https://docs.microsoft.com/en-us/azure/virtual-machines/windows/resize-vm

This question is poorly written... I assume you need to stop all of the ones in the availability set. Since you're resizing, that VM probably wasn't deallocated? https://docs.microsoft.com/en-us/azure/virtual-machines/troubleshooting/allocation-failure

I tried to upgrade to higher version in one of the server which part of availability set , Didnt receive any error.

According to the "allocation failure message", the VM1 virtual machine should be already stopped. So You should stop only VM2 and VM3? I am not really sure....