Correct Answer: A VM Scale Set consists of a set of identically configured VMs. Availability Set consists of a set of discrete VMs. No more than 20% of the Scale Set upgrading at any time, then 2 machines out of 10 will have maintenance, the 8 remaining VMs will be up. Virtual machine scale sets are created with five fault domains by default in Azure regions with no zones. 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. FD=1 in this case implies that the VM instances belonging to the scale set will be spread across many racks on a best effort basis. Reference: https://docs.microsoft.com/en-us/azure/virtual-machines/manage-availability https://docs.microsoft.com/en-us/learn/modules/build-app-with-scale-sets/2-features-benefits-virtual-machine-scale-sets https://docs.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-upgrade

Answer is wrong. The correct Answer is A. First: in case you created on fault domain, you are limited with one update domain. You can test this. Second: By default, Azure uses 5 update domains and up to 3 fault domains. So, In case you created 10 vm in scale set. then you will have 2 vm in each update domain. So once one update domain is not available, then you get 4 domains with 8 vms as required.

Answer is A. A-> UD is fixed at 5 for scale set. so during maintenance, 2 Vms will be down at each time. giving us at least 8VMs runing B-> Does not meet the min 8 virtual machines requirement c->Not possible. availability Set will spread out the VM into 2-3 FD depends on region. so min is 2 FD for high availability. ( Look at the comparision between scale sets and availability set under high availability in https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-orchestration-modes) D->will have min 9 or 10VM running

A is correct

The minimum number of fault domains required for an availability set containing 10 virtual machines is 31. Each fault domain represents a group of VMs that are placed in separate physical racks or clusters to minimize correlated failures. By distributing the VMs across fault domains, you enhance reliability and reduce the risk of simultaneous failures affecting related VMs. Additionally, an availability set can be configured with up to 20 update domains2. Update domains determine groups of VMs that can be rebooted together during planned maintenance. However, the order of update domains being rebooted may not proceed sequentially.

A is correct

This was on my exam. The correct answer is provided by the one and only mlantonis.

The update domain count must be 1 when fault domain count is 1. ANSWER IS A

Qustion said "during planned Azure maintenance", AD potentially could be even all down during planned Azure maintenance.

Don't panic guys, The Answer is A Reason : When you have 1 fault Domain you can have only 1 Update Domain. (Option C is ruled out)

There is a lot of confusion around this question. Whilst C can potentially be used in this scenario, the key here is that they specify only one Fault Domain. With one FD you can only create A SINGLE Update Domain, hence the only logical choice is A.

Correct Answer: A

The Answer here is C Let us first understand the distinction between Scaling and avalability. Scaling: Increase or decrease of VMs depending on loads Availability: Presence of VMs on multiple servers In these 2 definitions Scaling is automatic while availability is manual. In the question, there is a key statement which is "App1 always run on at least 8Vms" this means that App1 must be present on at least 8vms. Here, we don't have any concern with scaling up or scaling down. So, our answer is already tending towards AVAILABILITY SET Now, when you mention Availability set, you are already talking of Domains, both fault and update Now when we have 10 update domains, the app will be distributed into 2VMs per domain and since we have 2VMs per domain, whenever an upgrade is to be done, only 2VMs can go down at a single time making us have 8VM i.e 4 update domains available every time.

Tested in lab, its not possible to create an Availability Set with only one fault domain and 10 update domains. so C can't be right. I

Guys, WTF is going on here? C just can't be the good answer. First: I've just tried to create a new availability set. If the FD range-input is set to 1, then the UD range-input instantly gets disabled, and an info text box appears saying exactly this: "ℹ The update domain count must be 1 when fault domain count is 1." Second: Even if it would be possible to create the Availability Set this way, then it still would be empty. There won't be a single VM in it by default. IMHO in this case the answer should be something like "create an Availability Set and 10 VMs", or something like that, otherwise there will be exactly zero running VMs during that planned maintenance. Or anyway, how much VM will be deployed in this Availability Set after the planned move, based on answer C? 1? 8? 9? 10? 20? Or, what if it doesn't support the managed disks of the VMs? I think if we only stick to the original statements, without making any assumptions, then it's a right concern.

Correct Answer: C The question says during "Planned maintenance" so you look at Update domains NOT Fault domains like Answer A.

Azure Availability Set as per Chat GPT