Quick Answer
The answer is `.ebextensions/*.config` files, which are the traditional method for customizing the software and configuration of EC2 instances within an Elastic Beanstalk environment. These YAML or JSON configuration files, placed inside a `.ebextensions` folder at the root of your application bundle, allow you to define packages, files, services, and commands that run during instance provisioning, directly modifying the software stack on the EC2 instances. On the AWS Certified Developer Associate DVA-C02 exam, this concept tests your understanding of legacy versus modern customization methods; a common trap is confusing `.ebextensions` with the newer `.platform/hooks/` directory, which runs scripts at specific lifecycle events rather than declaratively configuring the instance. Remember that `.ebextensions` is for declarative configuration (what to install), while `.platform/hooks` is for imperative scripting (when to run it). A helpful memory tip: think of `.ebextensions` as the "extensions" that extend the base AMI with your custom software, making it the go-to choice for direct EC2 software customization.
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 developer is deploying a web application using AWS Elastic Beanstalk. Which TWO configuration files can be used to customize the software that runs on the EC2 instances? (Select TWO.)
.platform/hooks/
Used for custom platform hooks.
Dockerfile
Why wrong: Used for Docker environments, not general.
.ebextensions/*.config
Used for instance configuration.
appspec.yml
Why wrong: For CodeDeploy.
buildspec.yml
Why wrong: For CodeBuild.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
.platform/hooks/
Option A is correct because the `.platform/hooks/` directory is a feature of Elastic Beanstalk's platform-specific configuration that allows you to run custom scripts at specific lifecycle events (e.g., prebuild, postdeploy) on the EC2 instances. This is the modern replacement for the older `.ebextensions` approach for running commands during deployment, and it directly customizes the software running on the instances.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
.platform/hooks/
Why this is correct
Used for custom platform hooks.
Related concept
Read the scenario before looking for a memorised answer.
Dockerfile
Why it's wrong here
Used for Docker environments, not general.
.ebextensions/*.config
Why this is correct
Used for instance configuration.
Related concept
Read the scenario before looking for a memorised answer.
appspec.yml
Why it's wrong here
For CodeDeploy.
buildspec.yml
Why it's wrong here
For CodeBuild.
Common exam traps
The trap here is that candidates often confuse Elastic Beanstalk configuration files with other AWS services' configuration files (like CodeDeploy's appspec.yml or CodeBuild's buildspec.yml) or assume a Dockerfile is universally applicable, when in fact only `.platform/hooks/` and `.ebextensions/*.config` are the two valid options for customizing software on EC2 instances in Elastic Beanstalk.
Detailed technical explanation
Under the hood, Elastic Beanstalk uses platform hooks (in `.platform/hooks/`) to execute scripts at specific points in the deployment lifecycle, such as `prebuild`, `predeploy`, and `postdeploy`, with the scripts running as root on the EC2 instance. The `.ebextensions/*.config` files use YAML or JSON to define packages, sources, files, commands, and services via AWS CloudFormation, and they are processed by the Elastic Beanstalk service during environment creation and updates. A real-world scenario where this matters is when you need to install a custom monitoring agent (e.g., Datadog) on all instances; you would use a `.platform/hooks/postdeploy` script or an `.ebextensions` config to ensure it runs after the application is deployed.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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. 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
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Deployment — This question tests Deployment — Read the scenario before looking for a memorised answer..
The correct answer is: .platform/hooks/ — Option A is correct because the `.platform/hooks/` directory is a feature of Elastic Beanstalk's platform-specific configuration that allows you to run custom scripts at specific lifecycle events (e.g., prebuild, postdeploy) on the EC2 instances. This is the modern replacement for the older `.ebextensions` approach for running commands during deployment, and it directly customizes the software running on the instances.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 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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