AZ-104 Deploy and Manage Azure Compute Practice Question
A web tier must use identical VMs, keep the desired instance count if one instance becomes unhealthy, and allow future horizontal expansion without creating VMs one by one. What should the administrator deploy?
⚠ Common exam trap
Candidates often confuse an availability set's fault domain protection with automatic instance replacement, not realizing that availability sets only provide redundancy, not health-based remediation.
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 with health-based instance management.
A virtual machine scale set with health-based instance management is correct because it automatically maintains a desired number of identical VM instances, replaces unhealthy instances based on health probes, and supports horizontal scaling without manual VM creation. This aligns with the requirements for identical VMs, automatic instance replacement, and future expansion.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
An availability set because it automatically replaces unhealthy instances.
Why it's wrong here
An availability set is a logical grouping that spreads VMs across fault domains and update domains to maximize uptime during hardware failures and planned maintenance. However, it does not automatically create, remove, or recreate VMs; you must manually add VMs to the set, and it has no health monitoring or instance replacement logic. While it improves availability, it does not offer a managed way to maintain a target instance count or replace unhealthy instances, unlike a scale set.
When this WOULD be correct
An availability set would be correct if the requirement was to protect against hardware failures and planned maintenance by distributing VMs across multiple fault and update domains, without needing automatic instance replacement or scaling.
- ✓
A virtual machine scale set with health-based instance management.
Why this is correct
A virtual machine scale set provides a managed pool of identical VMs and is the right choice when you want Azure to maintain instance count and support horizontal growth. It works well for web tiers because the platform can replace unhealthy instances and let you scale up or down as demand changes. This removes the need to create and maintain each VM individually.
- ✗
An Azure Dedicated Host to keep the VMs on one physical server.
Why it's wrong here
An Azure Dedicated Host provides a physical server dedicated to your workloads, offering hardware isolation and control over maintenance, but it does not automatically maintain a desired VM count or replace unhealthy instances. You still must manually create and manage VMs on the host, and there is no native integration with health-based instance repair or autoscaling. It solves licensing/compliance requirements, not the need for a managed, self-healing pool of identical VMs.
When this WOULD be correct
An administrator needs to deploy VMs for a regulated workload that requires physical isolation from other customers, and the VMs must be placed on the same physical server to meet licensing or compliance requirements.
- ✗
A proximity placement group to ensure the VMs are distributed evenly.
Why it's wrong here
A proximity placement group is a logical grouping that places VMs close together to minimize network latency, but it does not manage instance count, provide health probing, or replace failed VMs. It is not a compute service and offers no built-in scaling or self-healing, so it cannot enforce a desired number of identical web-tier instances. In fact, over-constraining placement can even increase allocation failures, making it counterproductive for an auto-scaled web tier.
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 set with health-based instance management.Correct answer▾
Why this is correct
A virtual machine scale set provides a managed pool of identical VMs and is the right choice when you want Azure to maintain instance count and support horizontal growth. It works well for web tiers because the platform can replace unhealthy instances and let you scale up or down as demand changes. This removes the need to create and maintain each VM individually.
✗An availability set because it automatically replaces unhealthy instances.Wrong answer — click to see why▾
Why this is wrong here
An availability set does not automatically replace unhealthy instances; it only ensures VMs are distributed across fault and update domains for high availability. The question requires automatic health-based instance management, which availability sets lack.
★ When this WOULD be the correct answer
An availability set would be correct if the requirement was to protect against hardware failures and planned maintenance by distributing VMs across multiple fault and update domains, without needing automatic instance replacement or scaling.
Why candidates choose this
Candidates may confuse availability sets with automatic healing because both are related to high availability, but availability sets only provide redundancy, not automatic replacement of unhealthy VMs.
✗An Azure Dedicated Host to keep the VMs on one physical server.Wrong answer — click to see why▾
Why this is wrong here
An Azure Dedicated Host provides dedicated physical servers for compliance or licensing, but does not offer automatic health-based instance management or horizontal scaling; it would require manual VM creation and replacement.
★ When this WOULD be the correct answer
An administrator needs to deploy VMs for a regulated workload that requires physical isolation from other customers, and the VMs must be placed on the same physical server to meet licensing or compliance requirements.
Why candidates choose this
Candidates may think that keeping VMs on one physical server ensures identical performance and simplifies management, but they overlook that Dedicated Hosts do not provide auto-scaling or health replacement.
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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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.