AZ-900 Describe cloud concepts Practice Question
A retail company runs an e-commerce application on Azure. During the holiday season, the application experiences a sudden 10x increase in traffic. The company uses Azure Virtual Machine Scale Sets configured with autoscale rules based on CPU usage. The application automatically adds virtual machines during the peak and removes them when traffic subsides. Which benefit of cloud computing does this configuration primarily demonstrate?
⚠ Common exam trap
Many exam-takers confuse elasticity with high availability, but elasticity is specifically about scaling resources to meet demand, not about maintaining uptime through redundancy.
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
✓
Elasticity
This configuration demonstrates elasticity, which is the ability of a cloud system to automatically scale resources up or down based on demand. Azure Virtual Machine Scale Sets with autoscale rules based on CPU usage dynamically add VMs during traffic spikes and remove them when traffic subsides, directly matching resource allocation to workload requirements. This is a core benefit of cloud computing that enables cost efficiency and performance optimization 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.
- ✗
High availability
Why it's wrong here
High availability ensures that the application remains operational during failures (e.g., using multiple instances across availability zones). While the autoscale configuration can contribute to availability, the primary benefit shown here is the dynamic scaling based on demand, which is elasticity.
When this WOULD be correct
A company deploys a web application across multiple Azure availability zones to ensure it remains accessible even if one zone fails. The question asks which benefit this configuration primarily demonstrates.
- ✓
Elasticity
Why this is correct
Elasticity is the ability to automatically provision and de-provision resources to match current demand. The Virtual Machine Scale Sets with autoscale rules perfectly illustrate this by adding VMs when CPU usage rises and removing them when it falls, allowing the company to handle the holiday traffic spike efficiently.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance refers to the ability of a system to continue operating even if some components fail. Although Virtual Machine Scale Sets can be configured for fault tolerance, the scenario focuses on scaling based on demand, not on surviving failures.
When this WOULD be correct
A question describing an application that remains available and functional even when some VMs fail, using redundancy across availability zones or regions, would make fault tolerance the correct answer. For example: 'An e-commerce app runs on multiple VMs across two Azure regions. If one region fails, the app continues serving users from the other region.'
- ✗
Latency-based routing
Why it's wrong here
Latency-based routing is a traffic management feature that directs users to the nearest or fastest endpoint (e.g., using Azure Traffic Manager). It is not related to the ability to scale resources up or down based on workload.
When this WOULD be correct
A company deploys web servers in multiple Azure regions and wants to automatically route users to the region with the lowest latency. Using Azure Traffic Manager with latency-based routing would be 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-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓ElasticityCorrect answer▾
Why this is correct
Elasticity is the ability to automatically provision and de-provision resources to match current demand. The Virtual Machine Scale Sets with autoscale rules perfectly illustrate this by adding VMs when CPU usage rises and removing them when it falls, allowing the company to handle the holiday traffic spike efficiently.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability focuses on minimizing downtime and ensuring continuous operation, not on dynamically scaling resources up and down based on demand. The scenario describes adding and removing VMs in response to traffic changes, which is elasticity.
★ When this WOULD be the correct answer
A company deploys a web application across multiple Azure availability zones to ensure it remains accessible even if one zone fails. The question asks which benefit this configuration primarily demonstrates.
Why candidates choose this
Candidates may confuse elasticity with high availability because both involve multiple VMs and handling traffic spikes, but high availability is about redundancy and uptime, not dynamic scaling.
✗Fault toleranceWrong answer — click to see why▾
Why this is wrong here
Fault tolerance refers to a system's ability to continue operating despite component failures, not to dynamically scaling resources up and down based on demand. The scenario describes adding/removing VMs to handle traffic spikes, which is elasticity, not fault tolerance.
★ When this WOULD be the correct answer
A question describing an application that remains available and functional even when some VMs fail, using redundancy across availability zones or regions, would make fault tolerance the correct answer. For example: 'An e-commerce app runs on multiple VMs across two Azure regions. If one region fails, the app continues serving users from the other region.'
Why candidates choose this
Candidates may confuse fault tolerance with high availability or elasticity, thinking that automatically adding VMs during spikes also implies handling failures. The term 'fault' can be misinterpreted as any problem, including traffic surges.
✗Latency-based routingWrong answer — click to see why▾
Why this is wrong here
Latency-based routing directs traffic to the nearest or best-performing endpoint based on network latency, but the question describes scaling resources in response to traffic volume, not optimizing routing paths.
★ When this WOULD be the correct answer
A company deploys web servers in multiple Azure regions and wants to automatically route users to the region with the lowest latency. Using Azure Traffic Manager with latency-based routing would be the correct answer.
Why candidates choose this
Candidates may confuse 'scaling to handle traffic' with 'routing traffic efficiently,' as both involve managing increased load, but latency-based routing is about traffic direction, not resource scaling.
Analysis generated from the official AZ-900blueprint 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
What is Cloud Computing?
Key term
Cloud computing
Cloud computing is the on-demand delivery of IT resources over the internet, allowing users to access computing power, storage, and applications without owning physical hardware.
Key term
Workload
A workload is any discrete application, service, or function that runs on a computing resource, consuming CPU, memory, storage, or network capacity.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 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-900 exam.