The answer is to implement blue/green deployment on ECS with target tracking alarms to automate traffic shifting. This strategy directly addresses the need for risk reduction and fast rollback by maintaining two identical environments—the current "blue" production stack and the new "green" stack—so traffic can be gradually shifted via the Application Load Balancer only after the new tasks pass health checks. If a bug surfaces, you instantly revert traffic to the blue environment, avoiding the prolonged outage scenario described. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this question tests your understanding of deployment patterns that minimize blast radius, often contrasting blue/green with rolling or canary deployments. A common trap is choosing a rolling update, which lacks an instant rollback mechanism because it replaces tasks incrementally. Remember the mnemonic: "Blue is true, green is keen—if green breaks, blue retakes."
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 microservices application on Amazon ECS with Fargate. The application uses an Application Load Balancer (ALB) to route traffic to services. Each service has a required number of tasks for capacity. The company recently experienced a prolonged outage when a bug caused all tasks of the critical 'payment' service to crash simultaneously. The DevOps team needs to implement a deployment strategy that reduces the risk of a full service outage during updates. The strategy must also allow for quick rollback if a deployment fails. Which deployment strategy should the team implement?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Implement blue/green deployment using ECS with target tracking alarms to automate traffic shifting.
Blue/green deployment with target tracking allows you to gradually shift traffic to the new version while monitoring. If issues arise, you can instantly rollback by switching traffic back to the old version.
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.
✗
Implement a rolling update with a fixed number of tasks to replace at a time.
Why it's wrong here
Rolling updates can still cause brief capacity drops and rollback is slower.
✗
Use a canary deployment by creating a new service with a small number of tasks, test, then shift all traffic.
Why it's wrong here
Canary is a subset of blue/green but may require manual steps.
✗
Deploy changes during maintenance windows with manual approval steps.
Why it's wrong here
Manual processes are slow and error-prone.
✓
Implement blue/green deployment using ECS with target tracking alarms to automate traffic shifting.
Why this is correct
Blue/green with automated traffic shifting and rollback capability.
Related concept
Read the scenario before looking for a memorised answer.
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: Implement blue/green deployment using ECS with target tracking alarms to automate traffic shifting. — Blue/green deployment with target tracking allows you to gradually shift traffic to the new version while monitoring. If issues arise, you can instantly rollback by switching traffic back to the old version.
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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Question Discussion
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