AZ-900 Describe cloud concepts Practice Question
A company runs a web application on Azure virtual machines. The application experiences unpredictable traffic patterns with occasional sharp spikes. The operations team wants to configure the infrastructure so that the number of running virtual machines automatically increases during spikes and decreases during low traffic periods, without manual intervention. Which cloud computing characteristic does this requirement describe?
⚠ Common exam trap
Many candidates confuse elasticity with high availability, thinking that automatically adding VMs during spikes is about keeping the app available, but high availability is about redundancy and failover, not dynamic capacity adjustment.
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
Elasticity is the cloud computing characteristic that enables resources to automatically scale out (increase) during demand spikes and scale in (decrease) during low traffic periods, matching capacity to workload in real time. In Azure, this is implemented via Virtual Machine Scale Sets with autoscale rules based on metrics like CPU or memory thresholds, allowing the number of VMs to adjust 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 is incorrect because it aims to maximize uptime by minimizing service disruption, typically through redundant instances, load balancers, and failover mechanisms. It does not describe scaling resources up or down according to fluctuating load; an always-on, highly available system can still be completely inelastic.
When this WOULD be correct
A company runs a critical web application on Azure virtual machines and needs to ensure it remains accessible even if a single Azure region experiences an outage. The operations team wants to configure the infrastructure so that the application automatically fails over to another region without manual intervention.
- ✓
Elasticity
Why this is correct
Elasticity is the correct characteristic because Azure Virtual Machine Scale Sets can automatically add or remove VM instances based on real-time metrics such as CPU utilization, memory pressure, or custom application thresholds. This matches the requirement to handle variable demand without manual intervention, and you only pay for the VMs that are actually running at any given time.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance is incorrect because it focuses on the system's ability to continue functioning correctly even when a component (such as a VM, disk, or network path) fails. It is achieved through redundancy, replication, and graceful degradation, not through dynamic provisioning of additional compute capacity based on demand spikes.
When this WOULD be correct
A question asking about a system that must continue running despite hardware failures, such as 'A company requires that its application remains operational even if an Azure VM fails. Which characteristic is this?' would make fault tolerance correct.
- ✗
Geographic distribution
Why it's wrong here
Geographic distribution is incorrect because it refers to placing resources in multiple Azure regions or availability zones to reduce network latency for users in different locations, comply with data-residency laws, or provide regional failover. While it can complement scaling strategies, it does not automatically adjust the number or size of virtual machines in response to workload changes.
When this WOULD be correct
A company needs to ensure low latency for users worldwide and comply with data residency laws. The correct answer would be geographic distribution if the question asks about deploying resources in multiple Azure regions to serve users from nearby locations.
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 correct characteristic because Azure Virtual Machine Scale Sets can automatically add or remove VM instances based on real-time metrics such as CPU utilization, memory pressure, or custom application thresholds. This matches the requirement to handle variable demand without manual intervention, and you only pay for the VMs that are actually running at any given time.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures that the application remains accessible despite failures, but it does not automatically adjust capacity based on traffic spikes. The requirement is about scaling resources up and down, which is elasticity.
★ When this WOULD be the correct answer
A company runs a critical web application on Azure virtual machines and needs to ensure it remains accessible even if a single Azure region experiences an outage. The operations team wants to configure the infrastructure so that the application automatically fails over to another region without manual intervention.
Why candidates choose this
Candidates may confuse high availability with elasticity because both involve automated responses to maintain performance, but high availability focuses on uptime and redundancy, 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 without interruption when one or more components fail, not to automatically scaling resources up or down based on demand.
★ When this WOULD be the correct answer
A question asking about a system that must continue running despite hardware failures, such as 'A company requires that its application remains operational even if an Azure VM fails. Which characteristic is this?' would make fault tolerance correct.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve handling unexpected conditions, but fault tolerance focuses on failure recovery rather than dynamic scaling.
✗Geographic distributionWrong answer — click to see why▾
Why this is wrong here
Geographic distribution refers to deploying resources across multiple regions to reduce latency or meet compliance, not to automatically scaling resources up/down based on demand.
★ When this WOULD be the correct answer
A company needs to ensure low latency for users worldwide and comply with data residency laws. The correct answer would be geographic distribution if the question asks about deploying resources in multiple Azure regions to serve users from nearby locations.
Why candidates choose this
Candidates may confuse geographic distribution with elasticity because both involve multiple instances, but geographic distribution focuses on location rather than dynamic 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
Workload
A workload is any discrete application, service, or function that runs on a computing resource, consuming CPU, memory, storage, or network capacity.
Key term
Elasticity
Elasticity is the ability of a cloud system to automatically add or remove computing resources (like servers, storage, or bandwidth) in response to real-time changes in demand.
About these practice questions
One of 981 original AZ-900 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. 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-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.