The answer is the OneAtATime deployment configuration. This is correct because it shifts traffic to one new Amazon EC2 instance at a time, ensuring that only a single instance is taken out of service from the Auto Scaling group during the entire deployment process. By minimizing the number of instances removed at any given moment, it directly reduces service disruption and meets the developer’s requirement to keep as many instances serving traffic as possible. On the AWS Certified Developer Associate DVA-C02 exam, this question tests your understanding of CodeDeploy’s predefined deployment configurations and their impact on availability. A common trap is confusing OneAtATime with AllAtOnce, which would take all instances out of service simultaneously, or with HalfAtATime, which removes half the fleet. Remember the memory tip: “OneAtATime keeps the service line moving—only one instance steps out at a time.”
DVA-C02 Deployment Practice Question
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. A key principle to apply: oneAtATime is a predefined CodeDeploy deployment configuration.. 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 using AWS CodeDeploy to deploy an application to an Auto Scaling group of EC2 instances. The developer wants to minimize the number of instances that are taken out of service at any given time during the deployment. Which predefined deployment configuration should the developer use?
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: AllAtOnce deploys to all instances simultaneously, taking the entire fleet out of service during deployment, which does not minimize impact.
B
OneAtATime
OneAtATime updates only one instance at a time, keeping the rest serving traffic, thus minimizing the number of instances out of service.
C
HalfAtATime
Why wrong: HalfAtATime takes half of the instances out of service at a time, which is more disruptive than OneAtATime.
D
Custom with 50% at a time
Why wrong: A custom configuration that takes 50% out of service is similar to HalfAtATime and more disruptive than OneAtATime.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
OneAtATime
The OneAtATime deployment configuration shifts traffic to one new instance at a time, ensuring that only a single instance is taken out of service during the deployment. This minimizes the number of instances removed from the Auto Scaling group at any given moment, which directly meets the developer's requirement to reduce service disruption.
Key principle: OneAtATime is a predefined CodeDeploy deployment configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
AllAtOnce
Why it's wrong here
AllAtOnce deploys to all instances simultaneously, taking the entire fleet out of service during deployment, which does not minimize impact.
✓
OneAtATime
Why this is correct
OneAtATime updates only one instance at a time, keeping the rest serving traffic, thus minimizing the number of instances out of service.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
OneAtATime is a predefined CodeDeploy deployment configuration.
✗
HalfAtATime
Why it's wrong here
HalfAtATime takes half of the instances out of service at a time, which is more disruptive than OneAtATime.
✗
Custom with 50% at a time
Why it's wrong here
A custom configuration that takes 50% out of service is similar to HalfAtATime and more disruptive than OneAtATime.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates might confuse 'HalfAtATime' with a predefined configuration, but AWS CodeDeploy does not offer 'HalfAtATime' as a predefined option; the predefined options are 'AllAtOnce', 'OneAtATime', and 'Custom', so the correct choice is the one that minimizes instances taken out of service—OneAtATime.
Trap categories for this question
Similar concept trap
A custom configuration that takes 50% out of service is similar to HalfAtATime and more disruptive than OneAtATime.
Detailed technical explanation
How to think about this question
AWS CodeDeploy's predefined deployment configurations for in-place deployments include 'OneAtATime', which uses a batch size of 1 and a minimum healthy host percentage of 0 (or 100 depending on the configuration), ensuring only one instance is updated at a time. This is ideal for minimizing impact in production environments where even a small number of instances being unavailable can affect user experience. Under the hood, CodeDeploy orchestrates the deployment by stopping traffic to the single instance, deploying the revision, running hooks, and then re-registering it with the load balancer before proceeding to the next instance.
KKey Concepts to Remember
OneAtATime is a predefined CodeDeploy deployment configuration.
It updates only one instance at a time within the target group.
This configuration maximizes application availability during deployment.
It typically results in the longest overall deployment time among predefined options.
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
OneAtATime is a predefined CodeDeploy deployment configuration.
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. OneAtATime is a predefined CodeDeploy deployment configuration. 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.
Review oneAtATime is a predefined CodeDeploy deployment configuration., then practise related DVA-C02 questions on the same topic to reinforce the concept.
Deployment — This question tests Deployment — OneAtATime is a predefined CodeDeploy deployment configuration..
What is the correct answer to this question?
The correct answer is: OneAtATime — The OneAtATime deployment configuration shifts traffic to one new instance at a time, ensuring that only a single instance is taken out of service during the deployment. This minimizes the number of instances removed from the Auto Scaling group at any given moment, which directly meets the developer's requirement to reduce service disruption.
What should I do if I get this DVA-C02 question wrong?
Review oneAtATime is a predefined CodeDeploy deployment configuration., then practise related DVA-C02 questions on the same topic to reinforce the concept.
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?
OneAtATime is a predefined CodeDeploy deployment configuration.
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 →
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.