AZ-104 - Deploy and Manage Azure Compute Resources (24% of the exam) - Section 3.2

Create and configure virtual machines including availability options and virtual machine scale sets.

Select appropriate VM sizes for workload requirements and distinguish between availability sets, which protect against rack-level failures, and availability zones, which protect against datacenter-level failures. Configure virtual machine scale sets to automatically adjust capacity based on demand, and use VM extensions to automate post-deployment configuration.

VM sizesavailability setsavailability zonesvirtual machine scale setsVM extensions

Practice question for this objective

Free sampleDeploy and Manage Azure Compute Resourcesmedium

A Virtual Machine Scale Set runs several hundred instances. You want a scale-out action where a fixed increase would not noticeably improve performance, so each trigger should add instances relative to the current count. Which scale operation should the autoscale rule use?

  • AIncrease count by, which adds a fixed number of virtual machines on each trigger.
  • BIncrease count to, which creates instances up to a defined maximum amount.
  • CIncrease percent by, which scales the instance count by a percentage each trigger. Correct
  • DDecrease percent by, which removes a percentage of instances on each trigger.
Use percent-based scale operations on large scale sets and fixed-count operations on smaller ones. Increase percent by applies a percentage-based increase of virtual machines, which the documentation calls good for larger scale sets where a fixed increase may not noticeably improve performance.

Why A is wrong: Increase count by adds a fixed number, which the scenario explicitly rules out for a large scale set.

Why B is wrong: Increase count to creates as many instances as needed to reach a target maximum, not a relative growth per trigger.

Why C is correct: Correct. Increase percent by applies a percentage-based increase of virtual machines, which the documentation calls good for larger scale sets where a fixed increase may not noticeably improve performance.

Why D is wrong: Decrease percent by is a scale-in operation and reduces instances rather than scaling out.

See more AZ-104 practice questions, answers explained.

Exam traps in Deploy and Manage Azure Compute Resources

Answers that look right on this material and are not. Each one is a distractor from a different question in the AZ-104 bank for this domain.

  • Yes

    Why it is wrong: Saying yes ignores the documented prerequisite; autoscale has nothing to describe the instances it should create when no scaling profile exists.

  • It updates the platformFaultDomainCount property to redistribute the instances.

    Why it is wrong: platformFaultDomainCount controls fault domain spreading, not the manual instance count.

  • You can define up to 5 autoscale rules for a given scale set.

    Why it is wrong: Five is the Uniform update domain count, not the autoscale rule limit.

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