Elastic Beanstalk Rolling Deployment: Zero Downtime Updates
A company uses AWS Elastic Beanstalk to deploy a web application. The development team wants to ensure that the deployment does not cause any downtime and that new instances are fully registered with the load balancer before old instances are terminated. Which deployment policy should they use?
Quick Answer
The answer is rolling with an additional batch, as this deployment policy is specifically designed to minimize downtime by launching new instances in a separate batch, fully registering them with the load balancer, and only then terminating the old instances. This ensures that traffic is never dropped because the new instances are already serving requests before the old ones are removed, directly addressing the need for zero-downtime updates. On the AWS Certified Developer Associate DVA-C02 exam, this concept tests your understanding of how Elastic Beanstalk deployment policies handle capacity and traffic flow, with a common trap being to confuse standard rolling deployments—which can cause downtime if the batch size is too large—with the additional batch variant that maintains full capacity throughout. A helpful memory tip is to think of it as "add before you subtract," ensuring there is always a warm instance ready to take over.
⚠ Common exam trap
Candidates often confuse 'Rolling with an additional batch' with 'Immutable' deployment, but the key distinction is that Immutable creates a completely separate environment and swaps URLs, while Rolling with an additional batch operates within the same environment by temporarily adding extra instances.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Rolling with an additional batch
The Rolling with an additional batch deployment policy launches a new batch of instances in addition to the current ones, registers them with the load balancer, and only then terminates the old instances. This ensures zero downtime because the new instances are fully serving traffic before any old instances are removed, unlike standard rolling deployments which terminate old instances before new ones are fully ready.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Immutable
Why it's wrong here
Immutable deployments also ensure zero downtime but are not the only option; the question asks for a policy that ensures no downtime and full registration before termination.
- ✓
Rolling with an additional batch
Why this is correct
This policy adds new instances before removing old ones, ensuring zero downtime.
- ✗
Rolling
Why it's wrong here
Rolling deployments can cause downtime if the batch size is not configured properly.
- ✗
All at once
Why it's wrong here
All at once causes downtime.
Go deeper
Related to this question
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Same concept, more angles
3 more ways this is tested on DVA-C02
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 company uses AWS Elastic Beanstalk to deploy a web application. The developer has updated the application code and wants to deploy the new version with a rolling deployment strategy to minimize downtime. Which configuration should the developer use?
medium- ✓ A.Set the deployment policy to 'Rolling'
- B.Set the deployment policy to 'Immutable'
- C.Set the deployment policy to 'All at once'
- D.Set the deployment policy to 'Blue/green'
Why A: The 'Rolling' deployment policy in AWS Elastic Beanstalk updates instances in batches, moving the new application version into a subset of instances while keeping the rest serving traffic, which minimizes downtime by ensuring capacity is never fully reduced. This is the correct choice for a rolling update that balances speed and availability without requiring a full parallel environment.
Variation 2. A company uses AWS Elastic Beanstalk to deploy a web application. The developer wants to update the environment's configuration, such as instance type and environment variables, without causing downtime. Which deployment policy should the developer use?
easy- A.All at once
- B.Blue/green
- C.Immutable
- ✓ D.Rolling
Why D: The Rolling deployment policy is the correct choice because it updates instances in batches, replacing a subset of instances with the new configuration while keeping the rest running, thereby avoiding downtime. This allows environment variables and instance types to be changed incrementally without taking the entire application offline, as each batch is updated only after the previous batch remains healthy.
Variation 3. A developer is using AWS Elastic Beanstalk to deploy a web application. The developer needs to update the environment's configuration to use a larger instance type. What is the most efficient way to apply this change with minimal downtime?
easy- ✓ A.Update the environment configuration through the Elastic Beanstalk console or CLI, and use a rolling update strategy to apply the change to instances in batches.
- B.Perform a blue/green deployment by creating a new environment with the larger instance type, then swap the environment URLs.
- C.Modify the Auto Scaling group launch configuration directly to use the larger instance type, then manually terminate each instance.
- D.Terminate the current environment and create a new one with the larger instance type.
Why A: Elastic Beanstalk supports rolling updates, which allow you to change the instance type by updating instances in batches, minimizing downtime. Options B, C, and D are incorrect: B involves blue/green deployment, which is more complex and not the most efficient for a simple configuration change; C is wrong because directly modifying the Auto Scaling group launch configuration may be overwritten by Elastic Beanstalk and does not leverage Elastic Beanstalk's managed rolling update; D causes full downtime by terminating and recreating the environment.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.