Question 963 of 988
CLF-C02 Cloud Concepts Practice Question
A company runs a web application on a single Amazon EC2 instance. As the application gains popularity, the instance frequently reaches 100% CPU utilization during peak hours, causing slow response times. The operations team is evaluating two approaches: (1) migrate the application to a larger EC2 instance type with more CPU and memory, or (2) add multiple smaller EC2 instances behind a load balancer and distribute the traffic. Which cloud computing concept does approach (1) represent?
⚠ Common exam trap
Many candidates confuse vertical scaling with elasticity, but elasticity specifically refers to the dynamic, automated adjustment of resources (both up and down) to match demand, not a manual one-time upgrade to a larger instance.
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
✓
Vertical scaling
Approach (1) involves moving the application to a larger EC2 instance type with more CPU and memory, which is the definition of vertical scaling (scaling up). This increases the capacity of a single resource rather than adding more instances.
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 it's wrong here
Elasticity refers to the ability to automatically scale resources up or down based on demand. While the scenario may involve scaling, the specific action of changing to a larger instance type is vertical scaling, not the automated characteristic of elasticity.
When this WOULD be correct
A question describing a system that automatically adds or removes EC2 instances based on CPU utilization thresholds, such as using Auto Scaling groups and CloudWatch alarms, would make 'Elasticity' the correct answer.
- ✗
High availability
Why it's wrong here
High availability ensures that an application remains operational even if individual components fail. This scenario describes changing the size of a single instance, which does not inherently improve availability; in fact, a single larger instance can be a single point of failure.
When this WOULD be correct
A question asks: 'Which concept describes a system designed to minimize downtime by using redundant components across multiple Availability Zones?' In that context, High availability would be correct because it focuses on fault tolerance and continuous operation.
- ✓
Vertical scaling
Why this is correct
Vertical scaling (also called scaling up) increases the capacity of an existing resource by resizing the Amazon EC2 instance to a larger instance type with more vCPUs and memory. This is exactly approach (1) in the scenario, where a single EC2 instance is upgraded rather than adding new instances. Because the question asks specifically about changing to a larger instance, vertical scaling is the correct answer.
- ✗
Horizontal scaling
Why it's wrong here
Horizontal scaling (also called scaling out) adds additional EC2 instances to distribute the workload across multiple resources, typically behind a load balancer. Approach (2) in the scenario would be an example of horizontal scaling, but the question is about approach (1), which changes only the size of the existing single instance. Therefore, horizontal scaling is not the correct answer for the described action.
When this WOULD be correct
A scenario where the question asks: 'A company adds multiple EC2 instances behind a load balancer to handle increased traffic. Which concept does this represent?' — then horizontal scaling would be correct.
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.
✓Vertical scalingCorrect answer▾
Why this is correct
Vertical scaling (also called scaling up) increases the capacity of an existing resource by resizing the Amazon EC2 instance to a larger instance type with more vCPUs and memory. This is exactly approach (1) in the scenario, where a single EC2 instance is upgraded rather than adding new instances. Because the question asks specifically about changing to a larger instance, vertical scaling is the correct answer.
✗ElasticityWrong answer — click to see why▾
Why this is wrong here
Elasticity refers to the ability to automatically scale resources up or down based on demand, not simply migrating to a larger instance. Approach (1) is a manual, one-time upgrade, not an automated scaling response.
★ When this WOULD be the correct answer
A question describing a system that automatically adds or removes EC2 instances based on CPU utilization thresholds, such as using Auto Scaling groups and CloudWatch alarms, would make 'Elasticity' the correct answer.
Why candidates choose this
Candidates may confuse 'scaling up' (vertical scaling) with 'elasticity' because both involve increasing capacity, but elasticity specifically implies dynamic, automated adjustment rather than a static upgrade.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability refers to systems that remain operational despite component failures, typically achieved through redundancy and failover mechanisms. Approach (1) simply upgrades to a larger instance, which does not eliminate the single point of failure or improve availability.
★ When this WOULD be the correct answer
A question asks: 'Which concept describes a system designed to minimize downtime by using redundant components across multiple Availability Zones?' In that context, High availability would be correct because it focuses on fault tolerance and continuous operation.
Why candidates choose this
Candidates may confuse scaling with availability, thinking that any improvement in performance or capacity also enhances availability, but vertical scaling alone does not provide redundancy or fault tolerance.
✗Horizontal scalingWrong answer — click to see why▾
Why this is wrong here
Approach (1) involves increasing the size of a single instance, which is vertical scaling. Horizontal scaling (option D) would involve adding more instances, which is approach (2), not (1).
★ When this WOULD be the correct answer
A scenario where the question asks: 'A company adds multiple EC2 instances behind a load balancer to handle increased traffic. Which concept does this represent?' — then horizontal scaling would be correct.
Why candidates choose this
Candidates may confuse 'scaling up' (vertical) with 'scaling out' (horizontal) due to similar terminology, or mistakenly think adding resources always means adding more instances.
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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Last reviewed: Jun 11, 2026
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.
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