CLF-C02 Cloud Concepts Practice Question
A company runs an e-commerce application on AWS that experiences unpredictable traffic spikes during flash sales. The application currently runs on a fixed number of Amazon EC2 instances, which leads to performance degradation during spikes and wasted capacity during low traffic. The company wants to automatically adjust the number of instances based on real-time demand, only paying for the resources it uses. This need best represents which cloud computing concept?
⚠ Common exam trap
Test-takers frequently confuse elasticity with high availability, thinking that adding more instances automatically ensures uptime, but elasticity is specifically about dynamic scaling to match demand, not about redundancy or failure recovery.
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 correct because the scenario describes automatically scaling EC2 instances up and down based on real-time demand, which is the definition of elasticity in cloud computing. AWS Auto Scaling and Amazon EC2 Auto Scaling groups enable this by adding or removing instances in response to CloudWatch metrics, ensuring the application only pays for resources consumed during traffic spikes and low traffic periods.
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 a workload remains accessible despite component failures, typically by deploying redundant resources across multiple Availability Zones and using health checks or load balancers to reroute traffic. However, high availability is about maintaining uptime during failures, not about dynamically provisioning or de-provisioning capacity to match changing traffic levels. The described scenario demands automatic scaling in response to demand spikes and troughs, which high availability alone does not provide.
- ✓
Elasticity
Why this is correct
Correct. Elasticity refers to the ability to dynamically provision and de-provision resources to match workload changes. This scenario describes exactly that: automatically increasing instances during spikes and decreasing them during low traffic to optimize cost and performance.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance enables a system to continue operating, often with zero or minimal degradation, when one or more components fail, using approaches like redundant instances, failover, and highly available architectures. It is a design philosophy focused on masking failures, not on responding to changes in demand. In the scenario, traffic spikes are not failures; they are workload fluctuations, and fault tolerance does not include automatically adding or removing resources to match those fluctuations.
When this WOULD be correct
A question describing an application that must remain operational during an AWS Availability Zone outage, with requirements for automatic failover to redundant instances in another AZ, would make fault tolerance the correct answer.
- ✗
Durability
Why it's wrong here
Durability guarantees that data remains intact and recoverable over time, usually through replication, versioning, and backup mechanisms such as Amazon S3's 99.999999999% durability or RDS automated backups. This characteristic addresses data loss or corruption, not compute capacity or cost optimization. Adjusting instance counts during low traffic to reduce costs has no relationship to preserving data, making durability irrelevant to this scenario.
When this WOULD be correct
A question about ensuring that data stored in Amazon S3 remains intact even if an entire Availability Zone fails would make durability the correct answer, as it focuses on data persistence over time.
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 dynamically provision and de-provision resources to match workload changes. This scenario describes exactly that: automatically increasing instances during spikes and decreasing them during low traffic to optimize cost and performance.
✗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 automatically scaling resources based on demand. The question focuses on adjusting capacity to match traffic spikes, which is elasticity.
★ When this WOULD be the correct answer
A question describing an application that must remain operational during an AWS Availability Zone outage, with requirements for automatic failover to redundant instances in another AZ, would make fault tolerance the correct answer.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve handling unexpected events (failures vs. traffic spikes) and often use similar mechanisms like Auto Scaling groups, but fault tolerance specifically addresses system resilience to failures.
✗DurabilityWrong answer — click to see why▾
Why this is wrong here
Durability refers to the ability to recover data from failures, ensuring data is not lost, not to automatically adjusting compute capacity based on demand.
★ When this WOULD be the correct answer
A question about ensuring that data stored in Amazon S3 remains intact even if an entire Availability Zone fails would make durability the correct answer, as it focuses on data persistence over time.
Why candidates choose this
Candidates may confuse durability with elasticity because both involve handling failures or changes, but durability specifically addresses data preservation, not resource scaling.
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.