CLF-C02 Cloud Concepts Practice Question
A company runs a web application on a fleet of Amazon EC2 instances. The application experiences unpredictable traffic patterns with sudden spikes. The company configures an Auto Scaling group with dynamic scaling policies to automatically add instances when CPU utilization exceeds 70% and remove instances when it drops below 30%. This design is an example of which key characteristic of cloud computing?
⚠ Common exam trap
Candidates often confuse elasticity with high availability or fault tolerance, but elasticity specifically refers to dynamic scaling of resources to match demand, not 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
The Auto Scaling group's dynamic scaling policy, which adds instances when CPU utilization exceeds 70% and removes them when it drops below 30%, directly demonstrates elasticity. Elasticity is the ability to automatically provision and de-provision resources in response to real-time demand, matching capacity to workload without manual intervention. This contrasts with static provisioning, where resources are fixed regardless of load.
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 about keeping the application reachable and functional despite component failures, typically achieved by deploying redundant workloads across multiple Availability Zones and using health checks to fail over automatically. The scenario's dynamic Auto Scaling policy reacts to CPU utilization, not to instance failures or AZ outages, so it optimizes cost and performance but does not by itself guarantee uninterrupted availability. While scaling does add capacity, it does not replace the need for multi-AZ architecture or load balancing to maintain availability during an infrastructure failure.
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 configured to replace failed instances. This design is an example of which cloud characteristic?' Then high availability would be correct.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance means a system continues to function without interruption when a component fails. The described Auto Scaling behavior handles changes in demand, not failures, and does not guarantee zero interruption on individual instance failure.
When this WOULD be correct
A question describing an application that remains available and operational despite the failure of one or more EC2 instances, possibly using multiple Availability Zones and health checks, would make fault tolerance the correct answer.
- ✓
Elasticity
Why this is correct
Elasticity is the ability to automatically provision and deprovision computing resources to match current demand. The dynamic scaling policy that adds and removes instances based on CPU utilization is a direct implementation of elasticity in AWS.
- ✗
Durability
Why it's wrong here
Durability refers to the assurance that stored data will not be lost and can be reliably retrieved over time. This characteristic is associated with data storage services (e.g., Amazon S3's 99.999999999% durability), not compute scaling behavior.
When this WOULD be correct
A company stores critical financial records in Amazon S3 and needs to ensure that data is not lost even if a hardware failure occurs. The correct answer would be durability, as S3 is designed for 99.999999999% durability.
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
Elasticity is the ability to automatically provision and deprovision computing resources to match current demand. The dynamic scaling policy that adds and removes instances based on CPU utilization is a direct implementation of elasticity in AWS.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability refers to systems that remain operational despite component failures, not to automatic scaling based on demand. The scenario describes scaling resources up and down with traffic, which is elasticity, not high availability.
★ 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 configured to replace failed instances. This design is an example of which cloud characteristic?' Then high availability would be correct.
Why candidates choose this
Candidates may confuse high availability with elasticity because both involve multiple instances and Auto Scaling, but high availability focuses on 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 despite component failures, not to automatically scaling resources up and down based on demand. The scenario describes scaling based on CPU utilization, which is elasticity, not fault tolerance.
★ When this WOULD be the correct answer
A question describing an application that remains available and operational despite the failure of one or more EC2 instances, possibly using multiple Availability Zones and health checks, would make fault tolerance the correct answer.
Why candidates choose this
Candidates may confuse fault tolerance with elasticity because both involve handling unexpected changes, but fault tolerance focuses on surviving failures, not scaling to meet demand.
✗DurabilityWrong answer — click to see why▾
Why this is wrong here
Durability refers to the ability to retain data over time without loss, typically associated with storage services like Amazon S3. This question is about automatically scaling compute resources based on demand, which is elasticity, not durability.
★ When this WOULD be the correct answer
A company stores critical financial records in Amazon S3 and needs to ensure that data is not lost even if a hardware failure occurs. The correct answer would be durability, as S3 is designed for 99.999999999% durability.
Why candidates choose this
Candidates may confuse 'durability' with 'availability' or think it relates to maintaining system performance under load, but durability specifically concerns data persistence, 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.