AZ-104 Deploy and Manage Azure Compute Practice Question
The operations team wants 3 to 8 identical Linux VM instances, with more instances added when average CPU stays above 70 percent for 10 minutes and removed when load falls. Which three settings should be configured? Select three.
⚠ Common exam trap
It's easy for candidates to confuse availability sets with scale sets, thinking both provide scaling, but availability sets only offer redundancy and fault tolerance, not automatic scaling or instance count management.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use a virtual machine scale set for the identical application instances.
A virtual machine scale set (VMSS) is the correct Azure service for deploying and managing a group of identical, load-balanced Linux VMs that can automatically scale in and out based on demand. It supports autoscaling rules that adjust the instance count within a defined range, meeting the requirement for 3 to 8 identical instances with automatic addition when average CPU exceeds 70% for 10 minutes and removal when load falls.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use a virtual machine scale set for the identical application instances.
Why this is correct
A virtual machine scale set (VMSS) is the Azure compute service purpose-built to run multiple identical VM instances from a single configuration model. It provides built-in horizontal autoscaling, health monitoring, and centralized instance management, and can distribute instances across fault domains and availability zones. For a workload that needs 3–8 identical Linux instances that automatically adjust, VMSS is the correct foundation; it eliminates the need to manage each VM separately and enables declarative scaling policies.
- ✓
Create an autoscale profile with a scale-out rule based on average CPU utilization.
Why this is correct
The autoscale profile is the configuration that defines when and how the scale set changes capacity. A scale-out rule based on average CPU utilization — for example, scale out by one instance when average CPU exceeds 70% over a 10-minute evaluation window — directly matches the business requirement to add capacity under sustained load. This rule must be paired with cool-down timers and a scale-in rule to avoid rapid flapping, but the CPU threshold and grace period specified in the profile are what make automatic scaling responsive and predictable.
- ✓
Set minimum and maximum instance counts so the service cannot scale below 3 or above 8.
Why this is correct
Setting minimum and maximum instance counts creates a hard capacity boundary around the scale set: autoscale can never reduce below 3 instances or expand above 8, regardless of other metric thresholds. The minimum guarantees that the application always has at least three healthy instances to handle baseline traffic, while the maximum caps cost and prevents runaway scaling. These bounds are an essential part of the autoscale profile, and they align exactly with the 3-to-8 range the operations team specified.
- ✗
Place the VMs in an availability set instead of using a scale set.
Why it's wrong here
An availability set is designed for high availability by distributing VMs across fault domains and update domains, but it does not include any built-in mechanism to automatically add or remove VMs. If the workload grows, an administrator must manually create and attach new VMs; likewise, reducing capacity requires manual deallocation. While an availability set improves resilience, it fails the core requirement of automatic scaling based on CPU utilization, so it is not a substitute for a VM scale set in this scenario.
When this WOULD be correct
If the question required high availability for a fixed number of VMs (e.g., 3 VMs) without autoscaling, and the goal was to protect against hardware failures, an availability set would be the correct choice.
- ✗
Clone the VM manually whenever CPU rises and remove clones by hand later.
Why it's wrong here
Manually cloning a VM whenever CPU rises and removing clones by hand is operationally fragile and violates the requirement for automatic scaling. Manual actions are slow relative to load changes, prone to configuration drift because cloned instances must be individually updated, and offer no centralized monitoring or safe scale-in logic. This approach also requires continuous human attention and lacks the integration with autoscale policies that a purpose-built VMSS provides, making it both inefficient and unreliable for a dynamic workload.
When this WOULD be correct
This option would be correct in a scenario where the question specifies a small, static number of VMs (e.g., exactly 3) with no autoscaling requirement, and the candidate is asked to choose a manual deployment method for identical instances.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓Use a virtual machine scale set for the identical application instances.Correct answer▾
Why this is correct
A virtual machine scale set (VMSS) is the Azure compute service purpose-built to run multiple identical VM instances from a single configuration model. It provides built-in horizontal autoscaling, health monitoring, and centralized instance management, and can distribute instances across fault domains and availability zones. For a workload that needs 3–8 identical Linux instances that automatically adjust, VMSS is the correct foundation; it eliminates the need to manage each VM separately and enables declarative scaling policies.
✗Place the VMs in an availability set instead of using a scale set.Wrong answer — click to see why▾
Why this is wrong here
An availability set provides high availability for VMs but does not support autoscaling; it cannot automatically add or remove instances based on CPU load, which is required by the question.
★ When this WOULD be the correct answer
If the question required high availability for a fixed number of VMs (e.g., 3 VMs) without autoscaling, and the goal was to protect against hardware failures, an availability set would be the correct choice.
Why candidates choose this
Candidates may confuse availability sets with scale sets, thinking both provide scaling, or they may focus on high availability and overlook the explicit autoscaling requirement.
✗Clone the VM manually whenever CPU rises and remove clones by hand later.Wrong answer — click to see why▾
Why this is wrong here
Manual cloning and removal does not meet the requirement for automated scaling based on CPU thresholds; it lacks the autoscaling and orchestration capabilities of a scale set.
★ When this WOULD be the correct answer
This option would be correct in a scenario where the question specifies a small, static number of VMs (e.g., exactly 3) with no autoscaling requirement, and the candidate is asked to choose a manual deployment method for identical instances.
Why candidates choose this
Candidates may think manual cloning is a valid way to handle scaling for a small number of VMs, overlooking the automation and elasticity requirements in the question.
Analysis generated from the official AZ-104blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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About these practice questions
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Same concept, more angles
2 more ways this is tested on AZ-104
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You have a virtual machine scale set that must increase the number of instances automatically when average CPU utilization exceeds 75 percent and decrease when utilization drops below 30 percent. What should you configure?
hard- ✓ A.An Azure Monitor autoscale rule on the scale set
- B.A boot diagnostics configuration
- C.An availability set
- D.A custom script extension
Why A: Azure Monitor autoscale rules allow you to define conditions for automatically scaling out (increasing instances) when average CPU utilization exceeds a threshold (e.g., 75%) and scaling in (decreasing instances) when it drops below a lower threshold (e.g., 30%). These rules are applied directly to the virtual machine scale set, enabling dynamic scaling based on performance metrics.
Variation 2. A stateless Linux API should start with 2 instances, scale out to 6 when average CPU stays above 75 percent for 10 minutes, and scale back in when load drops. Which Azure compute resource should the administrator deploy?
medium- A.An availability set with manual VM resizing.
- ✓ B.A virtual machine scale set with autoscale rules.
- C.A single Standard D-series VM with scheduled shutdown.
- D.A load balancer in front of two unmanaged VMs.
Why B: A virtual machine scale set (VMSS) with autoscale rules is the correct choice because it natively supports scaling out and scaling in based on performance metrics like average CPU percentage. The requirement for a stateless Linux API with a minimum of 2 instances, scaling to 6 when CPU exceeds 75% for 10 minutes, and scaling back in when load drops is exactly the use case VMSS is designed for. Autoscale rules can be configured to use a scale-out and scale-in policy with a cool-down period, ensuring the application remains responsive while optimizing cost.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-104 exam.