The answer is to set the deployment minimum healthy percent to 50 and maximum percent to 100 with a health check grace period. This configuration prevents health check failure during an ECS deployment by ensuring that at least half of your tasks remain healthy and serving traffic while the new tasks are brought online; if the new tasks fail their health checks, the old tasks are never terminated, allowing an automatic rollback and preserving service availability. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of ECS deployment configuration to prevent health check failure, specifically how the rolling update strategy interacts with health check grace periods—a common trap is confusing maximum percent with the ability to replace all tasks at once, which would cause downtime. Remember the memory tip: “50 keeps the old alive, 100 lets the new arrive, and a grace period buys time for the first check.”
DOP-C02 Resilient Cloud Solutions Practice Question
This DOP-C02 practice question tests your understanding of resilient cloud solutions. 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 microservices architecture on Amazon ECS with Fargate. The services communicate via an internal Application Load Balancer. Recently, a new deployment of Service A caused its health checks to fail. The DevOps engineer notices that the old tasks remain running and the service is unavailable. What configuration change would prevent this issue in future deployments?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set the deployment minimum healthy percent to 50 and maximum percent to 100 with a health check grace period
Setting the deployment minimum healthy percent to 50 and maximum percent to 100 ensures that during a deployment, at least 50% of tasks are healthy, but if health checks fail, the deployment can roll back because the old tasks are not replaced until new tasks are healthy. Option B is wrong because it allows replacing all tasks before health checks pass. Option C is wrong because it is a deployment controller, not a configuration to prevent failure. Option D is wrong because it removes the ability to roll back.
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.
✓
Set the deployment minimum healthy percent to 50 and maximum percent to 100 with a health check grace period
Why this is correct
This configuration ensures old tasks remain until new tasks pass health checks.
Related concept
Read the scenario before looking for a memorised answer.
✗
Set the deployment circuit breaker to rollback on deployment failure and disable rollback
Why it's wrong here
Circuit breaker rolls back, but the question is about preventing the issue.
✗
Change the deployment controller from ECS to CodeDeploy for blue/green deployments
Why it's wrong here
Blue/green is a different approach but does not address the health check failure cause.
✗
Set the deployment minimum healthy percent to 0 and maximum percent to 200
Why it's wrong here
This allows all old tasks to be stopped before health checks pass.
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
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. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. 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.
Identify which DOP-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.
Resilient Cloud Solutions — This question tests Resilient Cloud Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set the deployment minimum healthy percent to 50 and maximum percent to 100 with a health check grace period — Setting the deployment minimum healthy percent to 50 and maximum percent to 100 ensures that during a deployment, at least 50% of tasks are healthy, but if health checks fail, the deployment can roll back because the old tasks are not replaced until new tasks are healthy. Option B is wrong because it allows replacing all tasks before health checks pass. Option C is wrong because it is a deployment controller, not a configuration to prevent failure. Option D is wrong because it removes the ability to roll back.
What should I do if I get this DOP-C02 question wrong?
Identify which DOP-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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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This DOP-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 DOP-C02 exam.
Question Discussion
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