The answer is 2. In a blue/green deployment with Amazon ECS using the Fargate launch type and AWS CodeDeploy, two ALB target groups are required because CodeDeploy manages traffic shifting by routing requests from the current (blue) target group to the new (green) target group, allowing the old environment to remain intact for instant rollback. A single target group cannot isolate the two environments during the transition, while three or more are unnecessary since only two active groups are needed at any point. On the AWS Certified Developer Associate DVA-C02 exam, this concept tests your understanding of how CodeDeploy integrates with ECS and ALB to achieve zero-downtime deployments; a common trap is assuming one target group is sufficient or that you need a separate group for each task definition revision. Remember the memory tip: “Blue and green, two groups are the scene”—you always need exactly two target groups to keep the old and new environments separate.
DVA-C02 Deployment Practice Question
This DVA-C02 practice question tests your understanding of deployment. 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 developer is deploying a containerized application to Amazon ECS with the Fargate launch type using AWS CodeDeploy for blue/green deployments. The application is behind an Application Load Balancer (ALB). What is the minimum number of ALB target groups required for a blue/green deployment?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Why wrong: A single target group cannot differentiate between blue and green environments; traffic would need to be manually swapped, defeating the purpose of blue/green.
B
2
Two target groups are needed—one for the running task set and one for the new task set. CodeDeploy shifts traffic between them.
C
3
Why wrong: Three target groups are not required; blue/green can be accomplished with exactly two target groups.
D
4
Why wrong: Four target groups are not necessary for a basic blue/green deployment; two suffice.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
2
In a blue/green deployment with Amazon ECS (Fargate) and AWS CodeDeploy, the deployment process requires two distinct target groups: one for the 'blue' (current) environment and one for the 'green' (new) environment. CodeDeploy shifts traffic from the blue target group to the green target group during the deployment, allowing for instant rollback by switching back. A single target group cannot differentiate between the two environments, and three or more are unnecessary because the blue/green model only needs two active target groups at any time.
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.
✗
1
Why it's wrong here
A single target group cannot differentiate between blue and green environments; traffic would need to be manually swapped, defeating the purpose of blue/green.
✓
2
Why this is correct
Two target groups are needed—one for the running task set and one for the new task set. CodeDeploy shifts traffic between them.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
3
Why it's wrong here
Three target groups are not required; blue/green can be accomplished with exactly two target groups.
✗
4
Why it's wrong here
Four target groups are not necessary for a basic blue/green deployment; two suffice.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume a single target group is sufficient because they think of the ALB as handling traffic routing on its own, but they miss that blue/green deployments require two separate target groups to isolate the old and new environments for traffic shifting and rollback.
Detailed technical explanation
How to think about this question
Under the hood, CodeDeploy orchestrates the blue/green deployment by registering the green task set with the second target group, then gradually updating the ALB listener rules to route traffic from the blue target group to the green target group. The original target group remains intact with the blue tasks, enabling an immediate rollback by reverting the listener rules. This two-target-group architecture is essential for zero-downtime deployments and is a core requirement in the AWS CodeDeploy integration with ECS.
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
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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Deployment — This question tests Deployment — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 2 — In a blue/green deployment with Amazon ECS (Fargate) and AWS CodeDeploy, the deployment process requires two distinct target groups: one for the 'blue' (current) environment and one for the 'green' (new) environment. CodeDeploy shifts traffic from the blue target group to the green target group during the deployment, allowing for instant rollback by switching back. A single target group cannot differentiate between the two environments, and three or more are unnecessary because the blue/green model only needs two active target groups at any time.
What should I do if I get this DVA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A developer is deploying a microservices application on Amazon ECS using Fargate. The developer wants to implement a blue/green deployment strategy using AWS CodeDeploy. The current production environment uses an Application Load Balancer (ALB). What is the minimum configuration required to enable blue/green deployments?
hard
✓ A.An ALB with two target groups, one for blue and one for green.
B.An ALB with a single target group and an Amazon CloudFront distribution.
C.An ECS service discovery namespace.
D.A Network Load Balancer (NLB) with a single target group.
Why A: Option A is correct because CodeDeploy blue/green requires an ALB and a target group for each environment. Option B is wrong because NLB also works but requires additional configuration. Option C is wrong because CloudFront is not required. Option D is wrong because ECS service discovery is not necessary.
Variation 2. A developer is deploying a microservices application on Amazon ECS with the Fargate launch type. The application uses an Application Load Balancer (ALB) to route traffic. The developer wants to perform a blue/green deployment with automated traffic shifting using AWS CodeDeploy. What is the minimum number of target groups required for this deployment?
hard
A.One
✓ B.Two
C.Three
D.Four
Why B: In a blue/green deployment with AWS CodeDeploy and an Application Load Balancer (ALB) on Amazon ECS (Fargate), two target groups are required: one for the 'blue' (current) environment and one for the 'green' (new) environment. CodeDeploy shifts traffic from the blue target group to the green target group by updating the ALB listener rules, allowing zero-downtime deployments and automated rollback if needed.
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.