- A
Configure an Amazon CloudFront distribution in front of the ALB to cache responses and absorb the spike.
Why wrong: CloudFront is a content delivery network (CDN) that caches static and dynamic content at edge locations. While caching can reduce load for repeated requests, it does not buffer dynamic request surges. It addresses latency and origin offload for cacheable content, not the temporary processing capacity shortage described in this scenario.
- B
Use an Amazon SQS queue between the ALB and the EC2 instances to decouple the request flow and buffer excess requests.
Amazon SQS is a fully managed message queuing service that can decouple application components. By placing an SQS queue between the ALB and the EC2 instances, incoming requests are stored as messages. The instances process messages at their own pace, buffering the excess during spikes. This ensures no requests are lost even when the spike exceeds the Auto Scaling group's maximum capacity.
- C
Enable Amazon EC2 Auto Scaling with predictive scaling to forecast and pre-provision capacity for the spikes.
Why wrong: Predictive scaling uses historical data to forecast future traffic and proactively adjust capacity. However, the spikes in this scenario are described as unpredictable, making accurate forecasting unreliable. Moreover, predictive scaling cannot provision capacity beyond the Auto Scaling group's maximum limit (2,000 instances), so it would still be insufficient during extreme spikes.
- D
Register additional EC2 instances in an on-premises data center as targets for the ALB and use manual failover.
Why wrong: This hybrid approach requires maintaining on-premises infrastructure and manual failover processes, which contradicts the requirement for no manual intervention. Additionally, integrating on-premises instances with an ALB typically involves a VPN or Direct Connect, adding complexity and latency. It does not provide the automatic buffering needed for unpredictable spikes.
Quick Answer
The answer is to use an Amazon SQS queue between the ALB and the EC2 instances to decouple traffic spikes. This works because SQS acts as a durable buffer, absorbing the sudden influx of up to 10,000 requests per second and storing them as messages, while the EC2 instances process them at their own steady pace from the queue. This ensures no requests are lost even when the Auto Scaling group’s maximum capacity is exceeded, and it eliminates the need for manual scaling or over-provisioning. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of decoupling architectures for handling unpredictable workloads—a core concept in the “Reliability” pillar of the Well-Architected Framework. A common trap is choosing to increase the Auto Scaling group’s maximum capacity, but that still risks hitting a hard limit; the key insight is that SQS provides elasticity without pre-planning the exact spike size. Memory tip: think of SQS as a “shock absorber” for traffic—it smooths out the bumps so your application never drops a request.
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. A key principle to apply: amazon SQS is a fully managed message queuing service.. 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 web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application normally handles 1,000 requests per second, but occasionally experiences unpredictable spikes of up to 10,000 requests per second for a few minutes. The Auto Scaling group is configured with a maximum capacity of 2,000 instances, which is insufficient to handle the spikes. The company must ensure that no requests are lost during these spikes without requiring manual scaling. Which solution 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
Use an Amazon SQS queue between the ALB and the EC2 instances to decouple the request flow and buffer excess requests.
Option B is correct because an Amazon SQS queue decouples the ALB from the EC2 instances, allowing the ALB to offload excess requests into the queue during traffic spikes. The EC2 instances then process messages from the queue at their own pace, ensuring no requests are lost even if the spike exceeds the Auto Scaling group's maximum capacity. This buffering mechanism handles unpredictable bursts without requiring manual intervention or pre-provisioning.
Key principle: Amazon SQS is a fully managed message queuing service.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure an Amazon CloudFront distribution in front of the ALB to cache responses and absorb the spike.
Why it's wrong here
CloudFront is a content delivery network (CDN) that caches static and dynamic content at edge locations. While caching can reduce load for repeated requests, it does not buffer dynamic request surges. It addresses latency and origin offload for cacheable content, not the temporary processing capacity shortage described in this scenario.
- ✓
Use an Amazon SQS queue between the ALB and the EC2 instances to decouple the request flow and buffer excess requests.
Why this is correct
Amazon SQS is a fully managed message queuing service that can decouple application components. By placing an SQS queue between the ALB and the EC2 instances, incoming requests are stored as messages. The instances process messages at their own pace, buffering the excess during spikes. This ensures no requests are lost even when the spike exceeds the Auto Scaling group's maximum capacity.
Related concept
Amazon SQS is a fully managed message queuing service.
- ✗
Enable Amazon EC2 Auto Scaling with predictive scaling to forecast and pre-provision capacity for the spikes.
Why it's wrong here
Predictive scaling uses historical data to forecast future traffic and proactively adjust capacity. However, the spikes in this scenario are described as unpredictable, making accurate forecasting unreliable. Moreover, predictive scaling cannot provision capacity beyond the Auto Scaling group's maximum limit (2,000 instances), so it would still be insufficient during extreme spikes.
- ✗
Register additional EC2 instances in an on-premises data center as targets for the ALB and use manual failover.
Why it's wrong here
This hybrid approach requires maintaining on-premises infrastructure and manual failover processes, which contradicts the requirement for no manual intervention. Additionally, integrating on-premises instances with an ALB typically involves a VPN or Direct Connect, adding complexity and latency. It does not provide the automatic buffering needed for unpredictable spikes.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume CloudFront can absorb any traffic spike, but it only helps with cacheable content and does not prevent request loss for dynamic, uncacheable workloads.
Trap categories for this question
Scenario analysis trap
CloudFront is a content delivery network (CDN) that caches static and dynamic content at edge locations. While caching can reduce load for repeated requests, it does not buffer dynamic request surges. It addresses latency and origin offload for cacheable content, not the temporary processing capacity shortage described in this scenario.
Detailed technical explanation
How to think about this question
Under the hood, an SQS queue acts as a durable buffer with a default retention period of 4 days and can store up to 120,000 in-flight messages per queue. The ALB can be configured to send HTTP 503 responses or redirect requests to an SQS queue via a Lambda function or by using the ALB's native integration with SQS through target groups of Lambda functions that write to the queue. In real-world scenarios, this pattern is commonly used for asynchronous processing of order submissions or log ingestion where request loss is unacceptable.
KKey Concepts to Remember
- Amazon SQS is a fully managed message queuing service.
- SQS decouples application components, improving fault tolerance.
- SQS can buffer millions of messages, preventing request loss during spikes.
- EC2 instances poll SQS queues to process messages asynchronously.
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
Amazon SQS is a fully managed message queuing service.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Amazon SQS is a fully managed message queuing service. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Review amazon SQS is a fully managed message queuing service., then practise related CLF-C02 questions on the same topic to reinforce the concept.
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FAQ
Questions learners often ask
What does this CLF-C02 question test?
Cloud Technology and Services — This question tests Cloud Technology and Services — Amazon SQS is a fully managed message queuing service..
What is the correct answer to this question?
The correct answer is: Use an Amazon SQS queue between the ALB and the EC2 instances to decouple the request flow and buffer excess requests. — Option B is correct because an Amazon SQS queue decouples the ALB from the EC2 instances, allowing the ALB to offload excess requests into the queue during traffic spikes. The EC2 instances then process messages from the queue at their own pace, ensuring no requests are lost even if the spike exceeds the Auto Scaling group's maximum capacity. This buffering mechanism handles unpredictable bursts without requiring manual intervention or pre-provisioning.
What should I do if I get this CLF-C02 question wrong?
Review amazon SQS is a fully managed message queuing service., then practise related CLF-C02 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Amazon SQS is a fully managed message queuing service.
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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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