AZ-104 Deploy and Manage Azure Compute Practice Question
A web front end must automatically add or remove instances based on demand. The application is stateless and all instances should be managed as one group. Which Azure service should you use?
⚠ Common exam trap
Watch out — candidates often confuse availability sets (which only provide fault tolerance) with auto-scaling, or mistakenly think that a single large VM can handle variable load by resizing, when the question explicitly requires automatic addition/removal of instances as a group.
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
✓
Virtual Machine Scale Set
Virtual Machine Scale Sets (VMSS) automatically scale the number of VM instances in or out based on demand or a defined schedule, making them ideal for stateless, horizontally scalable applications. They manage all instances as a single group behind a load balancer, ensuring uniform configuration and seamless scaling 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 Azure VM with a larger size
Why it's wrong here
Resizing a single VM vertically (larger size) only changes its SKU, which requires a restart and does not respond to load fluctuations automatically. It lacks any autoscale trigger, cannot dynamically add or remove compute nodes, and remains a single point of failure. Horizontal, instance-based scaling—the capability to start/stop VMs on demand—is not possible without a scale set.
When this WOULD be correct
For a stateless application that requires high performance and does not need auto-scaling, such as a dedicated database server or a single-instance application with predictable load, a single larger VM would be appropriate.
- ✓
Virtual Machine Scale Set
Why this is correct
A Virtual Machine Scale Set is designed for multiple similar VMs that need to scale together. It is a good fit for stateless workloads because instances can be added or removed without special per-VM configuration. You can also combine it with autoscale rules to respond to changing demand automatically.
- ✗
Availability set
Why it's wrong here
An availability set is a logical grouping that spreads VMs across fault domains and update domains to maximize resilience against hardware failures and planned maintenance. It has a fixed set of manually provisioned VMs and contains no scaling engine or metrics evaluation—it never changes the number of running instances. Availability sets improve uptime but cannot fulfill an autoscale requirement, which is a dynamic capacity control function.
When this WOULD be correct
You need to ensure that two or more VMs hosting a critical application remain available during planned or unplanned maintenance events, and you want to guarantee that they are placed on different fault and update domains.
- ✗
Managed disk snapshots
Why it's wrong here
Managed disk snapshots are point-in-time copies of operating system or data disks, used for backup, disaster recovery, or creating new disks. They are storage artifacts, not compute instances, so they can't execute code or serve web traffic. While a snapshot could theoretically seed a new VM, orchestrating that process automatically based on load is outside the snapshot's purpose; snapshots have no scaling or lifecycle management built in.
When this WOULD be correct
A question asks for a method to create a backup of a virtual machine's OS disk for disaster recovery purposes, where the backup should be stored as a managed resource.
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.
✓Virtual Machine Scale SetCorrect answer▾
Why this is correct
A Virtual Machine Scale Set is designed for multiple similar VMs that need to scale together. It is a good fit for stateless workloads because instances can be added or removed without special per-VM configuration. You can also combine it with autoscale rules to respond to changing demand automatically.
✗A single Azure VM with a larger sizeWrong answer — click to see why▾
Why this is wrong here
A single larger VM cannot automatically scale out/in based on demand; it only provides more resources for a single instance, not dynamic scaling across multiple instances.
★ When this WOULD be the correct answer
For a stateless application that requires high performance and does not need auto-scaling, such as a dedicated database server or a single-instance application with predictable load, a single larger VM would be appropriate.
Why candidates choose this
Candidates may think that a larger VM can handle increased load by itself, overlooking the need for automatic scaling and high availability across multiple instances.
✗Availability setWrong answer — click to see why▾
Why this is wrong here
An availability set provides high availability for VMs within a datacenter but does not support automatic scaling based on demand. It cannot add or remove instances automatically.
★ When this WOULD be the correct answer
You need to ensure that two or more VMs hosting a critical application remain available during planned or unplanned maintenance events, and you want to guarantee that they are placed on different fault and update domains.
Why candidates choose this
Candidates may confuse availability sets with scaling capabilities, thinking that the 'availability' in the name implies automatic scaling, or they may not fully understand the difference between high availability and auto-scaling.
✗Managed disk snapshotsWrong answer — click to see why▾
Why this is wrong here
Managed disk snapshots are point-in-time backups of disks, not a scaling solution. They cannot automatically add or remove instances based on demand.
★ When this WOULD be the correct answer
A question asks for a method to create a backup of a virtual machine's OS disk for disaster recovery purposes, where the backup should be stored as a managed resource.
Why candidates choose this
Candidates may confuse snapshots with scaling mechanisms, thinking snapshots can be used to create new instances quickly, but they lack automation and load-based scaling.
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
Managed Identities for Azure Resources
Key term
Load balancer
A load balancer is a device or software that distributes incoming network traffic across multiple servers so no single server gets overwhelmed.
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.
About these practice questions
Courseiva writes every AZ-104 question from scratch — 1,049 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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.