CLF-C02 Cloud Concepts Practice Question
A company runs an e-commerce website on Amazon EC2 instances behind an Application Load Balancer. The marketing team plans to run flash sales several times a year, which cause unpredictable but massive traffic spikes. The operations team wants the infrastructure to automatically add new EC2 instances when traffic increases and remove them when traffic decreases, without any manual intervention. Which cloud computing concept does this requirement MOST directly represent?
⚠ Common exam trap
Many exam-takers confuse scalability (the ability to grow) with elasticity (the ability to both grow and shrink automatically), but the question explicitly requires automatic addition and removal of instances, which is the defining characteristic of elasticity.
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
The requirement to automatically add EC2 instances during traffic spikes and remove them when traffic decreases directly represents elasticity. Elasticity is the ability to dynamically scale resources up or down based on real-time demand, which is precisely what the operations team needs for unpredictable flash sales. AWS Auto Scaling groups, integrated with the Application Load Balancer, automatically launch or terminate EC2 instances based on CloudWatch alarms (e.g., CPU utilization or request count), matching capacity to load 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.
- ✓
Elasticity
Why this is correct
Correct. Elasticity refers to the ability to automatically provision and de-provision resources in response to real-time demand. The described auto-scaling behavior that adds and removes EC2 instances during flash sales is the classic example of elasticity.
- ✗
Scalability
Why it's wrong here
Incorrect. While scalability involves the ability to increase capacity to handle growth, it does not inherently require automatic scaling down. The scenario specifically requires automatic removal of resources when traffic decreases, which is a key aspect of elasticity rather than scalability alone.
When this WOULD be correct
A question describing a planned, predictable increase in traffic (e.g., a known annual sale event) where the operations team manually provisions additional EC2 instances ahead of time and decommissions them after the event. In that scenario, scalability (specifically vertical or horizontal scaling) would be the correct concept.
- ✗
High availability
Why it's wrong here
High availability is incorrect because it refers to designing workloads to remain operational and accessible despite component failures, typically achieved through redundancy across multiple Availability Zones and automatic failover mechanisms. While the auto-scaling group may span AZs to maintain availability, the core behavior in this scenario is the dynamic addition and removal of EC2 instances in response to fluctuating traffic during flash sales. That capacity adjustment is the defining characteristic of elasticity, not high availability, which does not inherently involve scaling resources up or down based on demand.
When this WOULD be correct
A question asking about designing an architecture that remains operational during an Availability Zone failure, with instances distributed across multiple zones and automatic failover, would make high availability the correct answer.
- ✗
Fault tolerance
Why it's wrong here
Incorrect. Fault tolerance is the ability of a system to continue operating even when one or more of its components fail. The scenario does not describe failure recovery, but rather the scaling of resources to match fluctuating demand.
When this WOULD be correct
A question asking about a system that continues to function correctly despite the failure of one or more EC2 instances, such as using multiple Availability Zones and automatic failover.
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 refers to the ability to automatically provision and de-provision resources in response to real-time demand. The described auto-scaling behavior that adds and removes EC2 instances during flash sales is the classic example of elasticity.
✗ScalabilityWrong answer — click to see why▾
Why this is wrong here
Scalability refers to the ability to handle increased load by adding resources, but it does not inherently include the automatic addition and removal of resources in response to demand changes. The question specifically emphasizes automatic scaling based on unpredictable traffic spikes, which is the definition of elasticity.
★ When this WOULD be the correct answer
A question describing a planned, predictable increase in traffic (e.g., a known annual sale event) where the operations team manually provisions additional EC2 instances ahead of time and decommissions them after the event. In that scenario, scalability (specifically vertical or horizontal scaling) would be the correct concept.
Why candidates choose this
Candidates often confuse scalability with elasticity because both involve adding resources. They may think 'scalability' covers automatic scaling, but elasticity specifically implies dynamic, on-demand provisioning and deprovisioning to match fluctuating demand.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability focuses on ensuring the system remains operational and accessible despite failures (e.g., across multiple Availability Zones), not on automatically adjusting capacity in response to traffic spikes.
★ When this WOULD be the correct answer
A question asking about designing an architecture that remains operational during an Availability Zone failure, with instances distributed across multiple zones and automatic failover, would make high availability the correct answer.
Why candidates choose this
Candidates may confuse high availability with elasticity because both involve redundancy and automatic responses, but high availability is about uptime and fault tolerance, not dynamic scaling of resources.
✗Fault toleranceWrong answer — click to see why▾
Why this is wrong here
Fault tolerance focuses on maintaining system operation during component failures, not on automatically adjusting capacity to match demand spikes.
★ When this WOULD be the correct answer
A question asking about a system that continues to function correctly despite the failure of one or more EC2 instances, such as using multiple Availability Zones and automatic failover.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve automatic responses to changing conditions, but fault tolerance is about handling failures, not scaling to meet traffic changes.
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?”
Go deeper
Related to this question
About these practice questions
This CLF-C02 question is part of Courseiva's 988-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.