Welcome to ExamTopics
ExamTopics Logo
- Expert Verified, Online, Free.

Unlimited Access

Get Unlimited Contributor Access to the all ExamTopics Exams!
Take advantage of PDF Files for 1000+ Exams along with community discussions and pass IT Certification Exams Easily.

Exam AZ-104 topic 4 question 14 discussion

Actual exam question from Microsoft's AZ-104
Question #: 14
Topic #: 4
[All AZ-104 Questions]

You plan to move a distributed on-premises app named App1 to an Azure subscription.
After the planned move, App1 will be hosted on several Azure virtual machines.
You need to ensure that App1 always runs on at least eight virtual machines during planned Azure maintenance.
What should you create?

  • A. one virtual machine scale set that has 10 virtual machines instances
  • B. one Availability Set that has three fault domains and one update domain
  • C. one Availability Set that has 10 update domains and one fault domain
  • D. one virtual machine scale set that has 12 virtual machines instances
Show Suggested Answer Hide Answer
Suggested Answer: C ūüó≥ÔłŹ
An update domain is a logical group of underlying hardware that can undergo maintenance or be rebooted at the same time. As you create VMs within an availability set, the Azure platform automatically distributes your VMs across these update domains. This approach ensures that at least one instance of your application always remains running as the Azure platform undergoes periodic maintenance.
Reference:
http://www.thatlazyadmin.com/azure-fault-update-domains/

Comments

Chosen Answer:
This is a voting comment (?) , you can switch to a simple comment.
Switch to a voting comment New
mlantonis
Highly Voted 3 years ago
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
upvoted 238 times
gil906
2 months, 2 weeks ago
Thats true. " While you're upgrading a batch, there could be other concurrent planned or unplanned maintenance activities that could impact the health of your scale set instances. In such cases if more than 20% of the scale set's instances become unhealthy, then the scale set upgrade stops at the end of current batch." https://learn.microsoft.com/en-us/azure/virtual-machine-scale-sets/virtual-machine-scale-sets-automatic-upgrade#upgrading-vms-in-a-scale-set
upvoted 1 times
...
garmatey
1 year, 1 month ago
What part of the question indicates if the VMs are identical or discrete?
upvoted 1 times
...
morito
1 year, 2 months ago
"Virtual machine scale sets are created with five fault domains by default in Azure regions" I believe you're speaking of update domains?
upvoted 3 times
...
UWSFish
1 year, 1 month ago
I agree with everyone here saying that answer C will do the job. I wouldn't get hunf up on that. The final line does not say, "which of these choices will meet the requirements". it says, "What SHOULD you create" (emphasis mine). Which of the options is cleanest, most elegant, way forward. Clearly A.
upvoted 3 times
nightfxll
11 months, 2 weeks ago
Try making it and you can't. Only 1 update domain can be made if there is 1 fault domain and vice versa.
upvoted 7 times
...
KingHalik
6 months ago
I think you cannot create an availability set with more then one update and only one fault domain.
upvoted 1 times
...
...
...
fedztedz
Highly Voted 3 years, 5 months ago
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.
upvoted 210 times
valente_sven1
2 years, 9 months ago
Thank you, now i know why.
upvoted 1 times
...
DodgyD
3 years, 4 months ago
Well researched and explained. Appreciated! Agree. Very sneaky question leading us to think it is C when ans is A.
upvoted 6 times
...
QiangQiang
3 years, 3 months ago
but if A is good, then isn't D better, well costs more
upvoted 4 times
...
QiangQiang
3 years, 3 months ago
this is more like it. thanks
upvoted 3 times
...
...
smorar
Most Recent 6 days, 15 hours ago
Correct Answer: C Option A suggests using a virtual machine scale set (VMSS) consisting of 10 virtual machine instances. However, the requirement states that the application must run on at least eight virtual machines during planned Azure maintenance. The virtual machine scale set (VMSS) can automatically scale the number of virtual machine instances based on workload or defined scaling rules. However, it does not guarantee that there will be at least eight virtual machine instances running during planned maintenance. In contrast, option C proposes using an Availability Set with 10 update domains and one fault domain. This ensures that during planned maintenance, at least eight virtual machine instances will be available to run the application, meeting the specified requirement.
upvoted 1 times
...
summercat
1 month, 2 weeks ago
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
upvoted 1 times
...
bobothewiseman
1 month, 3 weeks ago
Selected Answer: A
A is correct
upvoted 1 times
...
Z_MU
2 months, 2 weeks ago
Selected Answer: A
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.
upvoted 1 times
Z_MU
2 months, 2 weeks ago
The minimum number of fault domains required for an availability set containing 10 virtual machines is 3*
upvoted 1 times
...
...
Amir1909
2 months, 3 weeks ago
A is correct
upvoted 1 times
...
PhoenixAscending
3 months, 2 weeks ago
Selected Answer: A
This was on my exam. The correct answer is provided by the one and only mlantonis.
upvoted 2 times
...
gyansinghnewdelhi
4 months ago
Selected Answer: A
The update domain count must be 1 when fault domain count is 1. ANSWER IS A
upvoted 1 times
...
31c21da
4 months ago
Selected Answer: C
Qustion said "during planned Azure maintenance", AD potentially could be even all down during planned Azure maintenance.
upvoted 1 times
...
Tilakarasu
4 months, 1 week ago
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)
upvoted 1 times
...
[Removed]
5 months, 1 week ago
Selected Answer: A
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.
upvoted 1 times
...
JoaoLoop10
5 months, 1 week ago
Selected Answer: A
Correct Answer: A
upvoted 1 times
...
BIOKU
5 months, 1 week ago
Selected Answer: C
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.
upvoted 1 times
...
93d821b
5 months, 2 weeks ago
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
upvoted 2 times
...
Bresic
6 months, 3 weeks ago
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: "‚ĄĻ 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.
upvoted 2 times
...
donniedarko
7 months, 2 weeks ago
Selected Answer: C
Correct Answer: C The question says during "Planned maintenance" so you look at Update domains NOT Fault domains like Answer A.
upvoted 1 times
...
Community vote distribution
A (35%)
C (25%)
B (20%)
Other
Most Voted
A voting comment increases the vote count for the chosen answer by one.

Upvoting a comment with a selected answer will also increase the vote count towards that answer by one. So if you see a comment that you already agree with, you can upvote it instead of posting a new comment.

SaveCancel
Loading ...