- A
Deploy the application across multiple AWS Regions and use Amazon Route 53 latency-based routing to failover.
Why wrong: This option addresses region-level failures, which is overkill and more expensive for a failure that is confined to a single Availability Zone. It also adds latency and complexity that are unnecessary for this scenario.
- B
Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.
This is correct because an Auto Scaling group that spans multiple Availability Zones will automatically replace a failed instance in a healthy Availability Zone, ensuring the application remains available even if one AZ goes down.
- C
Use a larger EC2 instance type with dedicated tenancy to reduce the risk of hardware failure.
Why wrong: A larger instance type or dedicated tenancy does not protect against an Availability Zone failure. It only changes the instance's capacity or isolation, not its dependence on a single AZ.
- D
Enable termination protection on the EC2 instance to prevent accidental stopping.
Why wrong: Termination protection only prevents an instance from being terminated through the AWS console or API. It does not help if the instance becomes unavailable due to an underlying power or infrastructure failure in the Availability Zone.
Quick Answer
The correct design principle is to place the EC2 instance in an Auto Scaling group with a minimum capacity of 1 and configure the group to span multiple Availability Zones. This works because the Auto Scaling group automatically detects when an instance in a failed zone becomes unhealthy and launches a replacement in a healthy zone, leveraging the multi-AZ failover capability inherent in the group’s configuration. Since the application is stateless and session data is stored externally in ElastiCache, the new instance can immediately serve traffic without data loss, achieving recovery within minutes. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of how Auto Scaling groups provide fault tolerance at the compute layer, often as a distractor against manually launching instances or relying solely on Elastic Load Balancing. A common trap is assuming a single-instance setup with an Elastic IP is sufficient, but that lacks automated recovery. Remember the memory tip: “ASG + multi-AZ = automatic failover for stateless apps.”
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 stateless web application on a single Amazon EC2 instance in the us-east-1a Availability Zone. The application stores session data in an external Amazon ElastiCache cluster. Due to a power failure in the data center hosting us-east-1a, the EC2 instance becomes unavailable. The company wants to redesign the architecture so that the application recovers automatically in minutes if a single Availability Zone fails. Which design principle should the company implement?
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
Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.
Option B is correct because placing the EC2 instance in an Auto Scaling group with a minimum capacity of 1 and spanning multiple Availability Zones ensures that if us-east-1a fails, the Auto Scaling group automatically launches a new instance in a healthy Availability Zone (e.g., us-east-1b). Since the application is stateless and session data is stored externally in ElastiCache, the new instance can immediately serve traffic without data loss, achieving recovery within minutes.
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.
- ✗
Deploy the application across multiple AWS Regions and use Amazon Route 53 latency-based routing to failover.
Why it's wrong here
This option addresses region-level failures, which is overkill and more expensive for a failure that is confined to a single Availability Zone. It also adds latency and complexity that are unnecessary for this scenario.
- ✓
Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones.
Why this is correct
This is correct because an Auto Scaling group that spans multiple Availability Zones will automatically replace a failed instance in a healthy Availability Zone, ensuring the application remains available even if one AZ goes down.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Use a larger EC2 instance type with dedicated tenancy to reduce the risk of hardware failure.
Why it's wrong here
A larger instance type or dedicated tenancy does not protect against an Availability Zone failure. It only changes the instance's capacity or isolation, not its dependence on a single AZ.
- ✗
Enable termination protection on the EC2 instance to prevent accidental stopping.
Why it's wrong here
Termination protection only prevents an instance from being terminated through the AWS console or API. It does not help if the instance becomes unavailable due to an underlying power or infrastructure failure in the Availability Zone.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse high-availability designs (multi-AZ Auto Scaling) with disaster recovery designs (multi-Region), or mistakenly think that instance-level protections like termination protection or larger instance types can mitigate an Availability Zone failure.
Trap categories for this question
Scenario analysis trap
This option addresses region-level failures, which is overkill and more expensive for a failure that is confined to a single Availability Zone. It also adds latency and complexity that are unnecessary for this scenario.
Detailed technical explanation
How to think about this question
Auto Scaling groups with multiple Availability Zones distribute instances across AZs and automatically replace failed instances using health checks. The minimum capacity of 1 ensures that the Auto Scaling group always maintains at least one running instance. When an AZ fails, the Auto Scaling group detects the unhealthy instance via EC2 status checks and launches a replacement in a different AZ, leveraging the stateless design and external ElastiCache for session persistence to achieve rapid recovery.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
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: Place the EC2 instance in an Auto Scaling group with a minimum capacity of 1, and configure the Auto Scaling group to span multiple Availability Zones. — Option B is correct because placing the EC2 instance in an Auto Scaling group with a minimum capacity of 1 and spanning multiple Availability Zones ensures that if us-east-1a fails, the Auto Scaling group automatically launches a new instance in a healthy Availability Zone (e.g., us-east-1b). Since the application is stateless and session data is stored externally in ElastiCache, the new instance can immediately serve traffic without data loss, achieving recovery within minutes.
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 →
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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