AZ-104 Deploy and Manage Azure Compute Practice Question
A line-of-business app runs on a single Azure VM in a region that supports availability zones. The business wants the VM to keep running if one datacenter in the region becomes unavailable. Which deployment choice best meets this requirement?
⚠ Common exam trap
It's easy for candidates to confuse availability sets (which protect against rack-level failures) with availability zones (which protect against datacenter-level failures), leading them to choose the set when the question explicitly requires datacenter outage protection.
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
✓
Availability zone
An availability zone is a physically separate datacenter within an Azure region, with independent power, cooling, and networking. Deploying the VM to a specific zone ensures it remains operational if another zone's datacenter fails, meeting the requirement for single-VM resilience against a datacenter outage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Availability set
Why it's wrong here
An availability set is a logical grouping that spreads VM instances across multiple fault domains and update domains within a single Azure datacenter. It protects against hardware failures (e.g., disk or rack failures) and Azure planned maintenance events, but because every fault domain and update domain is still inside the same building, a complete datacenter outage takes down all VMs in the set. It is a regional construct, not a zonal one, and cannot provide the datacenter-level isolation that availability zones offer.
When this WOULD be correct
If the requirement were to protect against hardware failures within a single datacenter (e.g., server or rack failure) while maintaining high availability for two or more VMs, an availability set would be the correct choice.
- ✓
Availability zone
Why this is correct
An availability zone is one of one or more physically separate datacenters within an Azure region, each with independent power, cooling, and network connectivity. Deploying the VM to a zone gives it a datacenter-level fault isolation boundary, which is the only construct among these choices that addresses a datacenter-wide outage. To fully survive a zone failure in practice, you would add a second instance in another zone, but the zone placement itself is the fundamental prerequisite for this level of protection.
- ✗
Proximity placement group
Why it's wrong here
A proximity placement group is an Azure feature that sacrifices fault-domain isolation for close physical proximity, grouping VMs together to minimize network latency for HPC or tightly coupled applications. All VMs in the group may end up in the same datacenter, even on shared hardware, making the entire group vulnerable to a single datacenter outage. It is a performance-optimization tool, not a high-availability (HA) design; it gives no guarantee of spreading workloads across independent failure domains.
- ✗
Virtual machine scale set
Why it's wrong here
A virtual machine scale set is an orchestration and auto-scaling service that can deploy many VM instances as a set, optionally across multiple availability zones if you explicitly configure zone spreading. Without that explicit configuration—or if it is deployed as a single-zone scale set—all instances are still subject to the same datacenter failure as a single VM. The scale set itself is not a high-availability feature; it simply exists to efficiently run a pool of identical VMs, and its default placement does not span physically isolated facilities.
When this WOULD be correct
A question requiring high availability and scalability for a stateless application that can run on multiple instances, such as a web front-end, where the requirement is to automatically add or remove VMs based on demand and survive zone failures by distributing instances across zones.
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.
✓Availability zoneCorrect answer▾
Why this is correct
An availability zone is one of one or more physically separate datacenters within an Azure region, each with independent power, cooling, and network connectivity. Deploying the VM to a zone gives it a datacenter-level fault isolation boundary, which is the only construct among these choices that addresses a datacenter-wide outage. To fully survive a zone failure in practice, you would add a second instance in another zone, but the zone placement itself is the fundamental prerequisite for this level of protection.
✗Availability setWrong answer — click to see why▾
Why this is wrong here
An availability set protects against failures within a single datacenter (e.g., rack or update domain failures) but does not provide resilience if an entire datacenter becomes unavailable, as all VMs in the set are in the same datacenter.
★ When this WOULD be the correct answer
If the requirement were to protect against hardware failures within a single datacenter (e.g., server or rack failure) while maintaining high availability for two or more VMs, an availability set would be the correct choice.
Why candidates choose this
Candidates may confuse availability sets with availability zones, thinking both provide datacenter-level redundancy, or they may assume 'availability' in the name implies full disaster recovery.
✗Virtual machine scale setWrong answer — click to see why▾
Why this is wrong here
Virtual Machine Scale Set provides auto-scaling and load balancing across multiple VMs, but it does not guarantee that a single VM continues running if a datacenter fails; it requires multiple instances and may not maintain the specific VM instance.
★ When this WOULD be the correct answer
A question requiring high availability and scalability for a stateless application that can run on multiple instances, such as a web front-end, where the requirement is to automatically add or remove VMs based on demand and survive zone failures by distributing instances across zones.
Why candidates choose this
Candidates may think that a scale set inherently provides availability zone resilience, but without configuring zone distribution, it only offers high availability within a single datacenter.
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
Availability zone
An Availability Zone is a distinct, isolated location within a cloud region that contains its own power, cooling, and networking, designed to protect applications from single points of failure.
Key term
Availability
Availability is the measure of how often a system or service is operational and accessible when needed, typically expressed as a percentage of uptime.
About these practice questions
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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.