CLF-C02 Cloud Concepts Practice Question
A company runs an e-commerce website on Amazon EC2 instances. The website experiences unpredictable traffic spikes during flash sales and returns to normal traffic levels afterward. To handle this, the company configures an Auto Scaling group that adds EC2 instances when the average CPU utilization exceeds 70% and removes instances when it drops below 30%. Which essential characteristic of cloud computing does this configuration primarily demonstrate?
⚠ Common exam trap
It's easy for candidates to confuse elasticity with high availability or fault tolerance, but the question specifically tests the ability to match resource capacity to fluctuating demand, which is elasticity, not the ability to withstand failures or remain operational.
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 because it automatically scales EC2 instances up during flash sales (when CPU exceeds 70%) and scales them down when traffic normalizes (CPU below 30%). Elasticity is the ability to dynamically provision and de-provision resources to match demand, which is exactly what Auto Scaling groups with CPU utilization thresholds achieve.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Elasticity
Why this is correct
Correct. Elasticity is the ability to automatically scale resources up or down to match demand. The Auto Scaling group adjusts the number of EC2 instances based on CPU utilization, which is a clear example of elasticity.
- ✗
High availability
Why it's wrong here
High availability is about keeping the application reachable and operational when failures occur—usually by distributing identical workloads across multiple Availability Zones and using failover mechanisms. The scenario's Auto Scaling group is reacting to CPU utilization, which adjusts capacity to match traffic, not to maintain uptime after an infrastructure failure. While Auto Scaling can also replace failed instances, the described trigger is load-based scaling, not a health-driven availability design.
When this WOULD be correct
A question that asks: 'A company deploys a web application across multiple Availability Zones with an Application Load Balancer and Auto Scaling group to maintain service even if an entire AZ fails. Which cloud characteristic does this demonstrate?' would have high availability as the correct answer.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance demands that the system continue operating without any interruption when a component fails, typically through active-active redundancy and automatic failover that requires no manual intervention. An Auto Scaling group driven solely by CPU utilization neither detects nor masks hardware or software component failures; it simply adds or removes instances as average utilization rises or falls. Thus, the architecture described is a demand-driven scaling mechanism, not a fault-tolerant design.
When this WOULD be correct
An exam question might ask: 'A company runs a critical application on multiple EC2 instances across Availability Zones. If one instance fails, the application continues running without downtime. Which cloud characteristic does this demonstrate?' The answer would be fault tolerance.
- ✗
Durability
Why it's wrong here
Durability concerns long-term data persistence, ensuring that stored data remains intact and recoverable against deletion or corruption, commonly via replication, versioning, and backup mechanisms such as Amazon S3 or EBS snapshots. The Auto Scaling group manages compute capacity by launching and terminating EC2 instances; it does not protect or preserve any data that resides on those instances. Therefore, durability is unrelated to the CPU-driven scaling behavior described in the question.
When this WOULD be correct
A question asking: 'Which cloud characteristic ensures that data remains intact and accessible even after hardware failures?' would make durability the correct answer, especially when discussing S3's 99.999999999% durability or EBS snapshots.
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 CLF-C02 exam frequently reuses these exact scenarios with slightly different constraints.
✓ElasticityCorrect answer▾
Why this is correct
Correct. Elasticity is the ability to automatically scale resources up or down to match demand. The Auto Scaling group adjusts the number of EC2 instances based on CPU utilization, which is a clear example of elasticity.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability focuses on ensuring system uptime and resilience through redundancy, not on dynamically scaling resources up and down based on demand. The question describes scaling in response to traffic spikes, which is elasticity.
★ When this WOULD be the correct answer
A question that asks: 'A company deploys a web application across multiple Availability Zones with an Application Load Balancer and Auto Scaling group to maintain service even if an entire AZ fails. Which cloud characteristic does this demonstrate?' would have high availability as the correct answer.
Why candidates choose this
Candidates may confuse elasticity with high availability because both involve Auto Scaling groups, but high availability is about fault tolerance and uptime, not dynamic scaling based on load.
✗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 scaling resources in response to demand changes. The question describes scaling based on CPU utilization, not handling failures.
★ When this WOULD be the correct answer
An exam question might ask: 'A company runs a critical application on multiple EC2 instances across Availability Zones. If one instance fails, the application continues running without downtime. Which cloud characteristic does this demonstrate?' The answer would be fault tolerance.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve multiple instances, but fault tolerance is about surviving failures, not scaling to meet load.
✗DurabilityWrong answer — click to see why▾
Why this is wrong here
Durability refers to the ability to retain data over the long term without loss, typically in storage systems like S3 or EBS. This question focuses on scaling compute resources in response to demand, not data persistence.
★ When this WOULD be the correct answer
A question asking: 'Which cloud characteristic ensures that data remains intact and accessible even after hardware failures?' would make durability the correct answer, especially when discussing S3's 99.999999999% durability or EBS snapshots.
Why candidates choose this
Candidates may confuse durability with reliability or assume it covers all forms of data protection, including the ability to handle traffic spikes, due to overlapping terminology in cloud concepts.
Analysis generated from the official CLF-C02blueprint 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 CLF-C02 practice question is part of Courseiva's free Amazon Web Services 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 CLF-C02 exam.