AZ-104 Deploy and Manage Azure Compute Practice Question
A company hosts a stateless web application behind a load balancer. Traffic increases during the day and drops at night. The team wants Azure to automatically add or remove identical VM instances based on demand. What should the administrator deploy?
⚠ Common exam trap
Many candidates confuse an availability set (which provides high availability) with a scale set (which provides elasticity), leading them to pick Option C because they think 'automatic addition/removal' means fault tolerance, not scaling.
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
✓
A virtual machine scale set
A virtual machine scale set (VMSS) is the correct choice because it automatically manages a group of identical, load-balanced VMs and can scale out (add VMs) or scale in (remove VMs) based on demand metrics like CPU usage or a schedule. This matches the requirement for a stateless web application with variable traffic, as VMSS integrates with Azure Load Balancer or Application Gateway and supports autoscale rules to handle daytime spikes and nighttime drops without manual intervention.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A single large virtual machine
Why it's wrong here
A single VM can be resized, but it cannot automatically add more identical instances to handle changing traffic. It also creates a larger single point of failure. This does not meet the requirement for elastic scale-out and scale-in behavior.
When this WOULD be correct
If the question specified a fixed, predictable workload that never varies and requires maximum performance for a single application instance, deploying a single large VM would be appropriate.
- ✓
A virtual machine scale set
Why this is correct
A virtual machine scale set is designed for deploying and managing multiple identical VMs as a group. It supports autoscaling rules so Azure can add or remove instances based on metrics such as CPU usage or scheduled demand. This is the best fit for a stateless web workload with changing traffic.
- ✗
An availability set
Why it's wrong here
An availability set improves VM placement for availability, but it does not automatically scale the number of instances. It helps with resilience, not elastic capacity management. You would still need to add or remove VMs manually.
When this WOULD be correct
An availability set would be correct if the question asked for a solution to ensure high availability and fault tolerance for a set of VMs, such as 'You need to guarantee that at least one VM remains available during planned maintenance or hardware failure.'
- ✗
A managed image
Why it's wrong here
A managed image is used as a source for creating new VMs. It does not by itself provide autoscaling, traffic-based instance management, or a runtime platform for handling web traffic. It is part of the deployment process, not the scaling solution.
When this WOULD be correct
A managed image would be correct if the question asked for a way to capture and reuse a VM configuration (e.g., 'You need to create multiple identical VMs from a customized OS disk. What should you create?').
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.
✓A virtual machine scale setCorrect answer▾
Why this is correct
A virtual machine scale set is designed for deploying and managing multiple identical VMs as a group. It supports autoscaling rules so Azure can add or remove instances based on metrics such as CPU usage or scheduled demand. This is the best fit for a stateless web workload with changing traffic.
✗A single large virtual machineWrong answer — click to see why▾
Why this is wrong here
A single large VM cannot automatically scale out/in based on demand; it lacks the elasticity to add or remove instances dynamically.
★ When this WOULD be the correct answer
If the question specified a fixed, predictable workload that never varies and requires maximum performance for a single application instance, deploying a single large VM would be appropriate.
Why candidates choose this
Candidates may think a large VM can handle variable loads by itself, overlooking the need for horizontal scaling and automated instance management.
✗An availability setWrong answer — click to see why▾
Why this is wrong here
An availability set provides high availability by distributing VMs across fault and update domains, but it does not support automatic scaling based on demand. The question requires automatic addition/removal of instances, which availability sets cannot do.
★ When this WOULD be the correct answer
An availability set would be correct if the question asked for a solution to ensure high availability and fault tolerance for a set of VMs, such as 'You need to guarantee that at least one VM remains available during planned maintenance or hardware failure.'
Why candidates choose this
Candidates may confuse availability sets with scale sets because both involve multiple VMs, and they might think availability sets also provide scaling capabilities, not realizing they only handle redundancy and placement.
✗A managed imageWrong answer — click to see why▾
Why this is wrong here
A managed image is a static template for creating VMs, not a scaling solution. It cannot automatically add or remove instances based on demand; it only provides a consistent configuration for manual or automated VM creation.
★ When this WOULD be the correct answer
A managed image would be correct if the question asked for a way to capture and reuse a VM configuration (e.g., 'You need to create multiple identical VMs from a customized OS disk. What should you create?').
Why candidates choose this
Candidates may think a managed image enables scaling because it can be used to create many VMs quickly, but it lacks the automatic scaling and load balancing integration that a scale set provides.
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?”
Go deeper
Related to this question
Learn chapter
VPN Gateway and ExpressRoute
Key term
Group
A group is a collection of users, devices, or other objects that are assigned permissions and policies together for simplified management in identity and governance systems like Microsoft Entra ID.
Key term
Azure Load Balancer
Azure Load Balancer is a cloud service that evenly distributes incoming network traffic across multiple virtual machines or resources to ensure reliability and high availability.
About these practice questions
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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.