DVA-C02 Deployment Practice Question
A company uses AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment fails with the error 'The overall deployment failed because too many individual instances failed deployment, too few healthy instances are available for deployment, or some instances in your deployment group are experiencing problems.' Which of the following is the MOST likely cause?
⚠ Common exam trap
Watch out — candidates often confuse deployment failures caused by health check failures with infrastructure issues like missing IAM roles or agents, but the specific error message about 'too many individual instances failed deployment' directly points to application-level health check failures, not permission or agent problems.
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
✓
The new application version fails the configured health checks on the instances.
The error message indicates that instances failed deployment, which is most commonly caused by the new application version failing the health checks configured in the deployment group. CodeDeploy uses these health checks (e.g., ELB health checks or custom scripts) to determine if an instance is healthy after deployment; if the application crashes or returns non-200 status codes, CodeDeploy marks the instance as failed and aborts the deployment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The new application version fails the configured health checks on the instances.
Why this is correct
CodeDeploy deployments are often configured with health checks, either through integration with Elastic Load Balancers or custom scripts defined in the `appspec.yml` file (e.g., in `AfterInstall` or `ApplicationStart` hooks). If the newly deployed application version fails to pass these configured health checks on the target instances, CodeDeploy automatically detects this issue. This failure triggers a pre-configured rollback to the last known good application version, ensuring service continuity and preventing the deployment of faulty code into production environments.
- ✗
The deployment group does not exist.
Why it's wrong here
A CodeDeploy deployment group is a fundamental resource that defines the target instances, deployment configuration, and lifecycle hooks for an application. If the specified deployment group does not exist when a deployment is initiated, CodeDeploy cannot identify where to deploy the application or which settings to apply. This scenario would result in an immediate deployment failure error, typically indicating that the resource cannot be found, rather than a rollback after the deployment has started.
- ✗
The IAM role for CodeDeploy does not have sufficient permissions.
Why it's wrong here
The IAM service role associated with CodeDeploy requires specific permissions to interact with other AWS services, such as EC2 for instance management, S3 for fetching application revisions, or CloudWatch for monitoring. If this role lacks necessary permissions, the deployment would fail early in its lifecycle, often with an "Access Denied" error or similar permission-related message. It would prevent CodeDeploy from performing actions like downloading the application bundle or updating instance tags, rather than triggering a rollback due to application health issues.
- ✗
The CodeDeploy agent is not installed on the instances.
Why it's wrong here
The CodeDeploy agent is a software package that must be installed and running on each target instance to facilitate deployments. Its primary function is to receive and execute deployment commands from the CodeDeploy service, including downloading application revisions and running `appspec.yml` hooks. If the agent is not installed or not running, CodeDeploy would report that the instances are unreachable or fail to register for the deployment, leading to a deployment failure status for those specific instances, but not necessarily a full rollback triggered by application health checks.
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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.