- A
The ALB health check interval is too short; increase the health check interval.
Short intervals cause healthy containers to be marked unhealthy, leading to 503 errors.
- B
The CPU threshold is too low; increase the target value to 80%.
Why wrong: Higher threshold means less scaling, likely increasing errors.
- C
The ALB idle timeout is too low; increase it to 300 seconds.
Why wrong: Idle timeout affects timeout errors (504), not 503.
- D
The cluster does not have enough EC2 instances; add more instances.
Why wrong: Fargate does not require EC2 instance management.
DVA-C02 Troubleshooting and Optimization Practice Question
This DVA-C02 practice question tests your understanding of troubleshooting and optimization. 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 containerized web application on Amazon ECS with Fargate launch type. The application experiences intermittent HTTP 503 errors. The ECS service auto-scales based on CPU, but the errors persist. What is the most likely cause and solution?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
The ALB health check interval is too short; increase the health check interval.
Option C is correct because 503 errors from ALB suggest targets failing health checks. Increasing health check thresholds gives targets more time to become healthy. Option A is wrong because increasing CPU threshold would reduce scaling, worsening errors. Option B is wrong because Fargate does not use a cluster of EC2 instances. Option D is wrong because errors are 503, not 504 (gateway timeout).
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.
- ✓
The ALB health check interval is too short; increase the health check interval.
Why this is correct
Short intervals cause healthy containers to be marked unhealthy, leading to 503 errors.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The CPU threshold is too low; increase the target value to 80%.
Why it's wrong here
Higher threshold means less scaling, likely increasing errors.
- ✗
The ALB idle timeout is too low; increase it to 300 seconds.
Why it's wrong here
Idle timeout affects timeout errors (504), not 503.
- ✗
The cluster does not have enough EC2 instances; add more instances.
Why it's wrong here
Fargate does not require EC2 instance management.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 DVA-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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Troubleshooting and Optimization — study guide chapter
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FAQ
Questions learners often ask
What does this DVA-C02 question test?
Troubleshooting and Optimization — This question tests Troubleshooting and Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The ALB health check interval is too short; increase the health check interval. — Option C is correct because 503 errors from ALB suggest targets failing health checks. Increasing health check thresholds gives targets more time to become healthy. Option A is wrong because increasing CPU threshold would reduce scaling, worsening errors. Option B is wrong because Fargate does not use a cluster of EC2 instances. Option D is wrong because errors are 503, not 504 (gateway timeout).
What should I do if I get this DVA-C02 question wrong?
Identify which DVA-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 20, 2026
This DVA-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 DVA-C02 exam.
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