CLF-C02 Cloud Concepts Practice Question
A company runs a customer-facing web application on a single Amazon EC2 instance. To improve resilience, the solutions architect decides to deploy a second EC2 instance in a different Availability Zone and configure an Application Load Balancer to distribute traffic. The goal is to ensure that the application remains accessible even if one instance or one Availability Zone becomes unavailable. Which cloud computing benefit does this architecture primarily aim to achieve?
⚠ Common exam trap
Candidates often confuse high availability with scalability or elasticity, mistakenly thinking adding more instances is always about handling more traffic rather than ensuring fault tolerance across Availability Zones.
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
✓
High availability
By deploying a second EC2 instance in a different Availability Zone and using an Application Load Balancer (ALB) to distribute traffic, the architecture ensures that if one instance or one Availability Zone fails, the ALB automatically routes traffic to the healthy instance in the other AZ. This design directly achieves high availability by eliminating a single point of failure and maintaining application uptime during infrastructure failures.
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 is the ability to automatically provision and de-provision resources in response to changing demand. While a multi-instance setup can support elasticity, the primary goal of the described architecture is to maintain service availability despite failures, not to dynamically adjust capacity.
When this WOULD be correct
An exam question describing a web application that experiences variable traffic patterns and requires automatic addition or removal of EC2 instances to match load would make elasticity the correct answer.
- ✓
High availability
Why this is correct
High availability ensures that a system remains operational even when components fail. Deploying EC2 instances in multiple Availability Zones behind a load balancer eliminates single points of failure and keeps the application accessible if an instance or an Availability Zone goes down. This directly addresses the requirement for resilience.
- ✗
Scalability
Why it's wrong here
Scalability is the ability to handle growing amounts of work by adding resources. Although deploying multiple instances can support scalability, the scenario specifically focuses on maintaining uptime during failures, not on handling increased traffic or growth.
When this WOULD be correct
A question where the application experiences variable traffic and the architect adds instances or auto-scaling to handle demand spikes, with the goal of maintaining performance under load.
- ✗
Cost optimization
Why it's wrong here
Cost optimization involves rightsizing resources and eliminating waste to minimize spending. The described architecture may increase costs due to running a second instance and a load balancer. While high availability can be part of a cost-benefit analysis, it is not the primary benefit the architecture aims to achieve.
When this WOULD be correct
A question that asks: 'A company wants to reduce its monthly EC2 spending by using Reserved Instances and right-sizing instances. Which benefit does this primarily achieve?' would make cost optimization the correct answer.
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.
✓High availabilityCorrect answer▾
Why this is correct
High availability ensures that a system remains operational even when components fail. Deploying EC2 instances in multiple Availability Zones behind a load balancer eliminates single points of failure and keeps the application accessible if an instance or an Availability Zone goes down. This directly addresses the requirement for resilience.
✗ElasticityWrong answer — click to see why▾
Why this is wrong here
Elasticity refers to automatically scaling resources up or down based on demand, not deploying across multiple Availability Zones for fault tolerance.
★ When this WOULD be the correct answer
An exam question describing a web application that experiences variable traffic patterns and requires automatic addition or removal of EC2 instances to match load would make elasticity the correct answer.
Why candidates choose this
Candidates may confuse the ability to add a second instance with scaling, but elasticity focuses on dynamic adjustment of capacity, not static redundancy for resilience.
✗ScalabilityWrong answer — click to see why▾
Why this is wrong here
Scalability refers to the ability to handle increased load by adding resources, but the primary goal here is ensuring application uptime despite failures, which is high availability.
★ When this WOULD be the correct answer
A question where the application experiences variable traffic and the architect adds instances or auto-scaling to handle demand spikes, with the goal of maintaining performance under load.
Why candidates choose this
Candidates may confuse adding instances for resilience with scaling, as both involve deploying more resources, but the key difference is the objective: availability vs. capacity.
✗Cost optimizationWrong answer — click to see why▾
Why this is wrong here
Cost optimization focuses on reducing expenses, not on ensuring application uptime during failures. The described architecture (multiple instances across AZs with a load balancer) is designed for high availability, not cost savings.
★ When this WOULD be the correct answer
A question that asks: 'A company wants to reduce its monthly EC2 spending by using Reserved Instances and right-sizing instances. Which benefit does this primarily achieve?' would make cost optimization the correct answer.
Why candidates choose this
Candidates may confuse cost optimization with high availability because running multiple instances can be seen as a cost-saving measure through redundancy, but the primary goal here is resilience, not cost reduction.
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.