Quick Answer
The answer is the rolling update deployment controller, which is the default for Amazon ECS. This controller achieves zero-downtime deployments by gradually replacing running tasks with new ones, using the minimum healthy percent and maximum percent settings to ensure capacity is never fully drained during an update. For automatic rollback on failure, you integrate CloudWatch alarms that trigger a return to the previous task definition if health checks fail. On the AWS Certified Developer Associate DVA-C02 exam, this question tests your understanding of native ECS controllers versus external options like CodeDeploy; a common trap is choosing blue/green, which is not a native ECS controller but requires AWS CodeDeploy. Remember: if the scenario mentions "native ECS" or "default behavior," think rolling update. Memory tip: "Rolling is the default, blue/green needs CodeDeploy."
This DVA-C02 practice question tests your understanding of deployment. 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. 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 wants to deploy a microservices application on Amazon ECS. They need to update services with zero downtime and automatic rollback on failure. Which deployment controller should they use?
Rolling update (ECS default)
Supports zero downtime and rollback.
External deployment controller
Why wrong: For external tools, not automatic rollback.
Daemon scheduling strategy
Why wrong: Not a deployment controller.
Blue/green deployment
Why wrong: Not a native ECS controller; requires CodeDeploy.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Rolling update (ECS default)
The correct answer is B. ECS supports rolling update (default) which gradually replaces tasks. With minimum healthy percent and maximum percent settings, zero downtime is possible, and rollback can be configured via CloudWatch alarms. Option A (Blue/green) is available via CodeDeploy, not native ECS controller. Option C (External) is for external deployments. Option D (Daemon) runs one task per instance.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Rolling update (ECS default)
Why this is correct
Supports zero downtime and rollback.
Related concept
Static NAT maps one inside address to one outside address.
External deployment controller
Why it's wrong here
For external tools, not automatic rollback.
Daemon scheduling strategy
Why it's wrong here
Not a deployment controller.
Blue/green deployment
Why it's wrong here
Not a native ECS controller; requires CodeDeploy.
Common exam traps
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
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. NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated. 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
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DVA-C02 NAT questions on configuration and troubleshooting.
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FAQ
Deployment — This question tests Deployment — Static NAT maps one inside address to one outside address..
The correct answer is: Rolling update (ECS default) — The correct answer is B. ECS supports rolling update (default) which gradually replaces tasks. With minimum healthy percent and maximum percent settings, zero downtime is possible, and rollback can be configured via CloudWatch alarms. Option A (Blue/green) is available via CodeDeploy, not native ECS controller. Option C (External) is for external deployments. Option D (Daemon) runs one task per instance.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DVA-C02 NAT questions on configuration and troubleshooting.
Static NAT maps one inside address to one outside address.
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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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