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Mitko4erto's avatar
Mitko4erto
Copper Contributor
Jan 26, 2021

Please, could you explain why the C option is the correct answer of that question.

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

 

Answer : C

  • ibnmbodji's avatar
    ibnmbodji
    Steel Contributor

    Mitko4erto 

     

    In a planned maintenance  when you have 5 update domains 4  are accessible while the 5th is updated and rebooted . So if you have 10 UD 2  vms will be rebooted while 8 will be accessible .

     

    0 1 2 3 4 5   --> 5 is  Off

    0 1 2 3 4 5   --> 5 is  Off 

     

    • azzouz180's avatar
      azzouz180
      Copper Contributor

      ibnmbodji 

      Option C clearly specifies that the fault domain is 1. When I try to setup an availability set with a fault domain of 1 in the portal, I get the following message "The update domain count must be 1 when fault domain count is 1." How can the C option be correct then?

       

      • ibnmbodji's avatar
        ibnmbodji
        Steel Contributor
        Didn't pay attention to "one" so you're right the C is not correct . It means also that there is no correct answer for this question .

  • Sumitchohan's avatar
    Sumitchohan
    Copper Contributor

    option A is correct answer. Azure will automatically distribute 10 VMs into five update zones evenly. So during planned maintenance of one update zone only 2 VMs will be affected

     

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