AZ-104 Deploy and Manage Azure Compute Practice Question
An application uses two Azure VMs in the same datacenter and must continue through planned maintenance and a single hardware host failure. The administrator does not need separate datacenter protection. Which option should be used?
⚠ Common exam trap
Many exam-takers confuse availability zones (which offer datacenter-level redundancy) with availability sets (which offer host-level redundancy within a single datacenter), leading them to choose zones even when the requirement explicitly states no separate datacenter protection is needed.
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 set
An availability set distributes VMs across multiple fault domains (hardware hosts) and update domains within a single Azure datacenter. This ensures that during planned maintenance (update domains) or a single hardware host failure (fault domains), at least one VM remains available. Since the requirement does not include separate datacenter protection, an availability set is the correct choice.
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 zones
Why it's wrong here
Availability zones are physically separate datacenters within an Azure region, each with independent power, networking, and cooling. While they provide high availability by isolating failures at the datacenter level, they exceed the requirement here, which only asks for protection against host-level or planned maintenance events within a single datacenter. Since the VMs are specified to be in the same datacenter, deploying them across zones would directly conflict with that constraint and introduce unnecessary cross-datacenter network latency and complexity.
When this WOULD be correct
A question requiring high availability and disaster recovery across datacenters within a region, such as: 'An application must remain available if an entire Azure datacenter fails. Which option should be used?'
- ✓
Availability set
Why this is correct
An availability set is designed to spread VMs across update and fault domains within a datacenter. That reduces the chance that maintenance or a host failure takes down all instances at once. Because the scenario only requires protection from host-level and planned maintenance events, an availability set is the appropriate and cost-effective choice.
- ✗
Proximity placement group
Why it's wrong here
A proximity placement group is designed to bring VMs closer together to minimize network latency, which is a performance optimization rather than an availability mechanism. It does not separate VMs into fault or update domains; in fact, it may place them on the same hardware, compounding the risk of a single host failure or maintenance event taking down all instances. The scenario requires redundancy against host and maintenance events, and a proximity placement group provides none of that—it could even make the situation worse by increasing the chance of correlated failures.
When this WOULD be correct
A question requiring the lowest latency between VMs in the same region, such as for tightly coupled workloads like HPC or real-time data processing, where availability against failures is not the primary concern.
- ✗
Virtual machine scale set
Why it's wrong here
A virtual machine scale set provides automatic scaling and load balancing by managing a large, identical set of VMs, and it can be configured with fault domains, but it is overkill for a fixed two-VM workload. The orchestration, scaling rules, and instance management overhead are unnecessary when the only requirement is to maintain availability across update and fault domains. An availability set achieves exactly that with minimal resources and no additional scaling complexity, making the scale set an inappropriate and overly complex choice for this scenario.
When this WOULD be correct
A question requiring automatic scaling of VMs based on demand, such as a web application that experiences variable traffic and needs to add or remove instances automatically, would make a virtual machine scale set the correct answer.
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 setCorrect answer▾
Why this is correct
An availability set is designed to spread VMs across update and fault domains within a datacenter. That reduces the chance that maintenance or a host failure takes down all instances at once. Because the scenario only requires protection from host-level and planned maintenance events, an availability set is the appropriate and cost-effective choice.
✗Availability zonesWrong answer — click to see why▾
Why this is wrong here
Availability zones provide datacenter-level redundancy across multiple physical locations within a region, but the question explicitly states no separate datacenter protection is needed. The requirement is only for protection against planned maintenance and a single hardware host failure, which an availability set handles within a single datacenter.
★ When this WOULD be the correct answer
A question requiring high availability and disaster recovery across datacenters within a region, such as: 'An application must remain available if an entire Azure datacenter fails. Which option should be used?'
Why candidates choose this
Candidates may confuse availability zones with availability sets, thinking both offer similar high availability, but zones provide broader fault isolation at the datacenter level, which is unnecessary here.
✗Proximity placement groupWrong answer — click to see why▾
Why this is wrong here
Proximity placement groups reduce network latency between VMs but do not provide high availability against planned maintenance or hardware failures. They lack fault domain and update domain isolation.
★ When this WOULD be the correct answer
A question requiring the lowest latency between VMs in the same region, such as for tightly coupled workloads like HPC or real-time data processing, where availability against failures is not the primary concern.
Why candidates choose this
Candidates may confuse proximity placement groups with availability sets because both involve grouping VMs, but proximity groups focus on performance, not fault tolerance.
✗Virtual machine scale setWrong answer — click to see why▾
Why this is wrong here
A virtual machine scale set provides auto-scaling and load balancing across multiple VMs, but it does not guarantee protection against planned maintenance or a single hardware host failure unless combined with an availability set or zones. The question specifies only two VMs and no need for scaling, making an availability set the simpler and correct choice.
★ When this WOULD be the correct answer
A question requiring automatic scaling of VMs based on demand, such as a web application that experiences variable traffic and needs to add or remove instances automatically, would make a virtual machine scale set the correct answer.
Why candidates choose this
Candidates may confuse scale sets with high availability because scale sets can distribute VMs across fault domains, but they are primarily for scaling, not for ensuring availability of a fixed number of VMs through planned maintenance.
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 set
An Availability set is a cloud computing feature that groups virtual machines across multiple fault domains and update domains to ensure high availability during hardware failures or planned maintenance.
Key term
Azure datacenter
An Azure datacenter is a physical facility that houses Microsoft's cloud computing infrastructure, including servers, storage, and networking equipment, to deliver Azure services globally.
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.