AZ-305 Design infrastructure solutions Practice Question
A company plans to deploy a stateless web application on Azure virtual machines. They want to ensure that the application remains available in the event of a hardware failure within a single Azure datacenter. The VMs must be placed in a way that ensures they are on different physical servers and racks, but are still within the same datacenter. Which deployment strategy should they use?
⚠ Common exam trap
Watch out — candidates often confuse Availability Zones (which span multiple datacenters) with Availability Sets (which operate within a single datacenter), leading them to select the zone-based option when the question explicitly requires staying within the same datacenter.
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
✓
Deploy the VMs in an Availability Set.
An Availability Set ensures that VMs are distributed across multiple fault domains (different physical servers, racks, and network switches) and update domains within a single Azure datacenter. This protects against hardware failures in that datacenter by guaranteeing that not all VMs are affected by the same local failure, while keeping them in the same datacenter for low-latency communication.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Deploy the VMs in an Availability Set.
Why this is correct
An Availability Set logically groups VMs so Azure distributes them across multiple fault domains (racks with independent power and network) and update domains (groups that are rebooted sequentially during planned maintenance). This contains hardware failures and maintenance events to a subset of the VMs, keeping your stateless web app reachable. It is the correct choice because the requirement is to protect against hardware failure within a single Azure datacenter.
- ✗
Deploy the VMs in different Availability Zones.
Why it's wrong here
Azure Availability Zones are physically separate datacenters within the same region, each with independent power, cooling, and networking. Choosing multiple zones protects against a complete datacenter failure, which goes beyond the stated need and increases cost and cross-datacenter latency. For protecting against rack-level hardware failure in a single datacenter, an Availability Set is the more targeted and cost-effective solution; also, zone deployment may require application-level support for zone redundancy.
- ✗
Deploy the VMs in a single Virtual Machine Scale Set with a large instance count.
Why it's wrong here
A Virtual Machine Scale Set with a large instance count is designed for elastic scaling, automatically adding and removing VM instances based on demand, and it does distribute instances across fault domains when using a single placement group. However, the goal here is not scalability—it is deterministic placement of a fixed set of VMs across hardware fault boundaries. Using a large scale set would over-provision compute resources, add management complexity, and give you less direct control over individual instance placement than an Availability Set.
- ✗
Deploy each VM in a separate resource group.
Why it's wrong here
Resource groups are logical containers used for grouping resources by environment, project, or owner for access control, tagging, and lifecycle management. They do not influence Azure's physical placement decisions—VMs in different resource groups can easily reside on the same physical host, rack, or datacenter. Therefore, separating VMs into distinct resource groups provides zero fault-domain or update-domain isolation and fails to meet the high-availability goal.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-305 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-305 exam.