- A
Elasticity
Why wrong: Elasticity refers to automatically provisioning and de-provisioning resources to match demand. While important for handling variable traffic, it does not directly address continued operation during a physical server failure.
- B
Scalability
Why wrong: Scalability is the ability to handle increasing workloads by adding resources. It focuses on growth and demand, not on maintaining operation when a specific component fails.
- C
Fault tolerance
Fault tolerance is the correct concept. The objective is to remain operational despite a hardware failure. AWS supports this by allowing resources to be deployed across multiple isolated Availability Zones, so a failure in one zone does not affect instances in another.
- D
Cost optimization
Why wrong: Cost optimization involves managing costs to maximize value. While fault-tolerant architectures may involve redundancy and additional cost, the primary objective described is about operational continuity, not cost reduction.
Quick Answer
The answer is fault tolerance. This is correct because fault tolerance is the AWS cloud concept that ensures an application continues operating without interruption even when a physical server or underlying component fails, typically by deploying redundant resources across multiple Availability Zones. For the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your ability to distinguish fault tolerance from high availability: fault tolerance means zero downtime during a failure, while high availability minimizes downtime but may allow brief interruptions. A common trap is confusing the two, but remember that fault tolerance is about surviving failure with no impact, whereas high availability focuses on quick recovery. A helpful memory tip is to think of fault tolerance as a “no-break” guarantee—the system keeps running seamlessly—while high availability is a “fix-it-fast” promise.
CLF-C02 Cloud Concepts Practice Question
This CLF-C02 practice question tests your understanding of cloud concepts. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company runs a critical web application on a single Amazon EC2 instance in a single Availability Zone. The company wants to design the architecture so that the application continues to operate even if the physical server hosting the instance fails. Which AWS Cloud concept does this design objective primarily address?
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
Fault tolerance
Fault tolerance is the correct concept because the design objective is to ensure continuous operation despite the failure of a physical server hosting the EC2 instance. This is achieved by deploying the application across multiple Availability Zones (AZs) using an Auto Scaling group and an Elastic Load Balancer, so that if one instance or AZ fails, traffic is automatically routed to healthy instances in another AZ. The scenario explicitly focuses on surviving infrastructure failure, which is the core definition of fault tolerance.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 automatically provisioning and de-provisioning resources to match demand. While important for handling variable traffic, it does not directly address continued operation during a physical server failure.
- ✗
Scalability
Why it's wrong here
Scalability is the ability to handle increasing workloads by adding resources. It focuses on growth and demand, not on maintaining operation when a specific component fails.
- ✓
Fault tolerance
Why this is correct
Fault tolerance is the correct concept. The objective is to remain operational despite a hardware failure. AWS supports this by allowing resources to be deployed across multiple isolated Availability Zones, so a failure in one zone does not affect instances in another.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Cost optimization
Why it's wrong here
Cost optimization involves managing costs to maximize value. While fault-tolerant architectures may involve redundancy and additional cost, the primary objective described is about operational continuity, not cost reduction.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse fault tolerance with high availability (HA), but the question specifically asks for the concept that ensures operation despite a physical server failure, which is fault tolerance, not just HA.
Detailed technical explanation
How to think about this question
Under the hood, fault tolerance in AWS relies on redundancy at multiple layers: deploying EC2 instances in at least two AZs, using an Elastic Load Balancer (ELB) with health checks to detect instance failure, and configuring Auto Scaling to replace unhealthy instances. A common real-world scenario is a web application using an Application Load Balancer (ALB) with a target group spanning us-east-1a and us-east-1b; if the physical server in us-east-1a fails, the ALB automatically routes traffic to the healthy instance in us-east-1b, achieving a Recovery Time Objective (RTO) of seconds.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this CLF-C02 question test?
Cloud Concepts — This question tests Cloud Concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Fault tolerance — Fault tolerance is the correct concept because the design objective is to ensure continuous operation despite the failure of a physical server hosting the EC2 instance. This is achieved by deploying the application across multiple Availability Zones (AZs) using an Auto Scaling group and an Elastic Load Balancer, so that if one instance or AZ fails, traffic is automatically routed to healthy instances in another AZ. The scenario explicitly focuses on surviving infrastructure failure, which is the core definition of fault tolerance.
What should I do if I get this CLF-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on CLF-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company runs a customer-facing web application with an Amazon RDS database. Initially, the database is deployed as a single instance in one Availability Zone (AZ). A power outage occurs in that AZ, causing the database to become unavailable for several hours. After the incident, the company modifies the database to use a Multi-AZ configuration. Shortly after the change, another power outage affects the same primary AZ. This time, the database automatically fails over to the standby instance in the other AZ without any manual intervention, and the application remains available. Which cloud computing concept does this scenario best demonstrate?
medium- A.Elasticity
- ✓ B.Fault tolerance
- C.Scalability
- D.Resource pooling
Why B: Fault tolerance is the ability of a system to continue operating without interruption when one or more of its components fail. In this scenario, the Multi-AZ RDS deployment automatically failed over to a standby instance in a different Availability Zone when the primary AZ experienced a power outage, ensuring the application remained available without manual intervention. This demonstrates fault tolerance because the system was designed to withstand the failure of an entire AZ and continue functioning.
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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