DVA-C02 Deployment Practice Test 19 — 15 Questions

Question 1

A startup is deploying a Node.js application using AWS Elastic Beanstalk. They have configured the environment to use a load-balanced, auto-scaled environment with a minimum of 2 instances and a maximum of 4. The application connects to an Amazon RDS MySQL database. After a successful deployment, users report that the application is intermittently returning errors. The developer checks the Elastic Beanstalk logs and finds that the application is timing out when connecting to the database. The developer also notices that the database connection string is hardcoded in the application code. What is the most likely cause of the intermittent errors?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

The RDS instance has reached its maximum number of concurrent connections because the application instances are not using connection pooling.. The RDS instance has reached its maximum number of concurrent connections because the application instances are not using connection pooling. In a load-balanced, auto-scaled Elastic Beanstalk environment with 2-4 Node.js instances, each instance opens its own database connections, and without connection pooling or Amazon RDS Proxy, the total can exceed the MySQL max_connections limit, producing intermittent connection timeouts under load. Option A is unlikely because a security group misconfiguration would typically cause consistent, not intermittent, connection failures across all instances. Option C is not supported by the symptom of timeouts when connecting, which points to connection exhaustion rather than premature closure. Option D is irrelevant because lack of Multi-AZ affects availability during an AZ failure, not routine intermittent connection timeouts.

Answer

The security group for the RDS instance does not allow inbound traffic from the Elastic Beanstalk environment's security group.

Answer

The application code has a bug that causes the database connection to be closed prematurely.

Answer

The RDS instance is not configured for Multi-AZ deployment, causing failover issues.

Question 2

A company is using AWS CodePipeline to automate the deployment of a microservices application to Amazon ECS. The pipeline has the following stages: Source (GitHub), Build (CodeBuild), Deploy (ECS). The Deploy stage uses an ECS task definition and updates the service. Recently, the pipeline failed at the Deploy stage with the error: 'The task definition family is inactive.' The developer checks the ECS console and sees that the task definition family exists but is inactive. The developer also notices that the pipeline uses a parameter 'TASK_DEFINITION_FAMILY' with the value 'my-app'. What is the most likely cause?

Accepted Answer

The pipeline is referencing the task definition family name without a specific revision number, and the latest revision is inactive.. The error 'The task definition family is inactive' indicates that the pipeline is using the task definition family name 'my-app' without specifying a revision number. When a task definition family is marked as inactive, it means the latest revision in that family is inactive. CodePipeline requires a specific active revision number to deploy successfully. Therefore, the most likely cause is that the pipeline is referencing only the family name, and the latest revision is inactive. Option D correctly identifies this issue. Option A is incorrect because the family exists. Option B is incorrect because environment variables are unrelated to the error. Option C is incorrect because the pipeline's IAM role permissions are not the issue; the error is about the task definition state, not permissions.

Answer

The task definition family 'my-app' does not exist in the ECS cluster.

Answer

The environment variables in the task definition are not correctly set.

Answer

The IAM role for ECS does not have permission to register new task definitions.

Question 3

A company uses AWS CodeCommit for source control and AWS CodeBuild for building a Java application. They have a CodePipeline that deploys the built artifacts to an Auto Scaling group using CodeDeploy. Recently, the build stage started failing with the error: 'BUILD FAILED: Could not resolve dependencies for project'. The developer checks the buildspec.yml and sees that it uses Maven to download dependencies from a private repository. The developer also notices that the build environment is a managed Docker image. What is the most likely cause?

Accepted Answer

The build environment does not have network access to the private Maven repository because it is not configured with a VPC.. CodeBuild runs in a managed Docker image that, by default, has internet access but no route to private VPC resources such as an internal Maven repository. To reach a private repository hosted inside a VPC, the CodeBuild project must be configured with VPC settings (VPC ID, subnets, security groups). Without that, Maven cannot resolve dependencies and the build fails.

Answer

The CodeBuild project does not have the necessary IAM permissions to access the private Maven repository.

Answer

The buildspec.yml has a syntax error in the 'phases' section.

Answer

The Java compiler version is incompatible with the project.

Question 4

A company is deploying a microservices application on Amazon ECS using the Fargate launch type. The application includes a service that must process messages from an Amazon SQS queue. The developer wants to ensure that the service scales based on the number of messages in the queue. Which scaling solution should the developer implement?

Accepted Answer

Use Amazon ECS Service Auto Scaling with a target tracking scaling policy based on the SQS queue backlog per task.. Amazon ECS Service Auto Scaling with a target tracking scaling policy based on the SQS queue backlog per task (calculated as ApproximateNumberOfMessages divided by the number of running tasks) directly correlates the number of ECS tasks to the queue depth. This ensures the service scales up when messages accumulate and scales down when the backlog clears, using a predefined or custom metric that reflects the workload.

Answer

Configure DynamoDB auto scaling to adjust read capacity based on queue depth.

Answer

Configure AWS Lambda with reserved concurrency and trigger it from the SQS queue.

Answer

Use Application Auto Scaling with a scheduled scaling policy to increase the number of tasks during peak hours.

Question 5

A development team wants to automatically deploy a web application to Amazon EC2 instances when new code is pushed to the master branch of an AWS CodeCommit repository. Which AWS service should the team use to orchestrate the build, test, and deployment phases?

Accepted Answer

AWS CodePipeline. AWS CodePipeline is the correct service because it is a fully managed continuous delivery service that orchestrates the entire build, test, and deployment phases as a pipeline. It can be configured to automatically trigger on code pushes to the master branch of an AWS CodeCommit repository, then invoke AWS CodeBuild for building and testing, and finally deploy to EC2 instances via AWS CodeDeploy, providing end-to-end automation.

Answer

AWS CloudFormation

Answer

AWS CodeBuild

Answer

AWS CodeDeploy

Question 6

A company is using AWS CodeDeploy to deploy a web application to an Auto Scaling group. The deployment fails with the error message 'The overall deployment failed because too many individual instances failed deployment, too few healthy instances are available, or some instances in your deployment group are experiencing problems.' The developer checks the deployment logs and finds that the ApplicationStop hook failed on some instances. What is the most likely cause of this failure?

Accepted Answer

The ApplicationStop script is not compatible with the instance operating system or is missing.. The error message indicates that the ApplicationStop hook failed on some instances. The ApplicationStop hook is a lifecycle event that runs a script to stop the application before a new deployment begins. If the script is missing, incompatible with the instance's operating system, or has incorrect permissions, it will fail, causing the deployment to abort. This is the most direct cause of the failure described.

Answer

The ValidateService hook script is failing.

Answer

The BeforeInstall hook script is incorrectly configured.

Answer

The Auto Scaling group does not have enough capacity to perform the deployment.

Question 7

A developer is deploying a serverless application using AWS SAM. The application consists of an API Gateway endpoint that triggers an AWS Lambda function. The developer wants to enable canary deployments to gradually shift traffic to a new Lambda version. Which SAM resource attribute should the developer configure?

Accepted Answer

AutoPublishAlias and DeploymentPreference. `AutoPublishAlias` automatically creates and updates a Lambda alias (e.g., `live`) that points to the latest version of your function, while `DeploymentPreference` enables canary, linear, or all-at-once traffic shifting between the old and new alias versions. Together, they allow gradual traffic migration to a new Lambda version without manual alias management.

Answer

ReservedConcurrentExecutions

Answer

Timeout

Answer

ProvisionedConcurrency

Question 8

A developer is deploying a new version of an AWS Lambda function using the AWS CLI. The developer wants to create a new version and update the alias to point to the new version. Which sequence of CLI commands should the developer use?

Accepted Answer

Update function code, publish version, update alias. The correct sequence is to first update the function code, then publish a new version, and finally update the alias to point to that new version. The `update-function-code` command uploads the new code to the $LATEST version, `publish-version` creates an immutable numbered version from $LATEST, and `update-alias` updates the alias to reference that specific version. This ensures the alias always points to a stable, published version rather than the mutable $LATEST.

Answer

Update alias, update function code, publish version

Answer

Create alias, update function code, publish version

Answer

Publish version, update function code, update alias

Question 9

A developer is using AWS CodeDeploy to deploy a revision to an EC2/On-Premises deployment group. The deployment fails because the specified deployment configuration requires a minimum of 1 healthy host, but the deployment group has 0 instances. What is the most likely cause?

Accepted Answer

The deployment group does not have any Amazon EC2 instances registered.. The deployment failed because the deployment group had zero registered instances, making it impossible to meet the minimum of 1 healthy host required by the deployment configuration. Option D is correct because the error message directly indicates that the deployment group contains no EC2 instances, so there are no hosts to deploy to.

Answer

The deployment group is not associated with any Auto Scaling group.

Answer

The deployment configuration requires too many healthy hosts.

Answer

The CodeDeploy agent is not installed on the instances.

Question 10

A developer is designing a CI/CD pipeline for a serverless application using AWS CodePipeline. The pipeline must automatically build and deploy the application when changes are pushed to a CodeCommit repository. The application uses AWS CloudFormation for infrastructure provisioning. Which TWO actions should the developer include in the pipeline?

Accepted Answer

Use AWS CodeBuild to run unit tests and package the application.. AWS CodeBuild can compile source code, run unit tests, and produce deployment artifacts, which is a standard build phase in a CI/CD pipeline. Option E is correct because AWS CloudFormation is the native AWS service for provisioning and updating infrastructure as code, making it the appropriate deployment action for a serverless application defined in templates.

Answer

Use AWS CodeDeploy to deploy the application to EC2 instances.

Answer

Use AWS CodeCommit as a deployment action.

Answer

Use AWS Lambda to run integration tests.

Question 11

A developer is deploying a new version of an AWS Lambda function. The function is behind an API Gateway endpoint. The developer wants to use canary deployments to gradually shift traffic to the new version. Which TWO steps should the developer perform?

Accepted Answer

Create a Lambda alias that points to the current version and configure routing to shift a percentage of traffic to the new version.. Lambda aliases support traffic shifting for canary deployments by allowing you to route a percentage of incoming requests to a new function version while the majority continues to the current version. This is done by configuring the alias's routing configuration with a `RoutingConfig` that specifies the new version and the weight (e.g., 5%) of traffic it should receive. This enables gradual, controlled rollouts without modifying the API Gateway integration endpoint. Option C is also necessary because the API Gateway integration must point to the Lambda alias (rather than a fixed version) so that the routing configuration on the alias can take effect. Without updating the integration to use the alias, API Gateway would continue to invoke a specific version directly, bypassing the canary routing.

Answer

Configure Amazon CloudFront to distribute traffic between two API Gateway endpoints.

Answer

Update the Lambda function code and publish a new version.

Answer

Create a new API Gateway stage for the new version and update DNS.

Question 12

A company is using AWS CloudFormation to deploy and manage infrastructure. The developer wants to implement a CI/CD pipeline that automatically deploys CloudFormation stacks. The pipeline should be able to create, update, and delete stacks. Which THREE AWS services should the developer use together?

Accepted Answer

AWS CodeBuild. AWS CodeBuild is correct because it can be used as a build and test action within a pipeline to run custom scripts (e.g., using the AWS CLI) that create, update, or delete CloudFormation stacks. In a CI/CD pipeline, CodeBuild can execute `aws cloudformation deploy` or `aws cloudformation delete-stack` commands, providing the flexibility to handle stack operations beyond simple template deployment.

Answer

AWS CodeDeploy

Answer

AWS Lambda

Question 13

Refer to the exhibit. A developer creates this CloudFormation template and tries to deploy it. The deployment fails with 'CREATE_FAILED' for the S3 bucket resource. What is the most likely cause?

Accepted Answer

The bucket name is already taken by another AWS account.. S3 bucket names must be globally unique across all AWS accounts. If the bucket name specified in the template is already in use by another account, CloudFormation will fail with CREATE_FAILED for the S3 bucket resource. This is a fundamental requirement of the S3 service, not a template syntax or configuration issue.

Answer

The template does not enable versioning on the bucket.

Answer

The bucket name must be in all lowercase letters.

Answer

The template does not specify a bucket policy.

Question 14

Refer to the exhibit. A developer is troubleshooting a failed CodeDeploy deployment to an EC2 Auto Scaling group. The instance logs show that the 'BeforeInstall' script failed with exit code 1. What should the developer do to resolve the issue?

Accepted Answer

Review the BeforeInstall script for errors and fix them.. The 'BeforeInstall' script failed with exit code 1, which is a generic error indicating the script itself encountered an issue during execution. The developer should review the script for errors, such as syntax mistakes, missing dependencies, or incorrect commands, and fix them. This is the most direct and appropriate action because the failure is explicitly tied to the script's execution, not to infrastructure or permissions.

Answer

Ensure the CodeDeploy agent is installed and running on the instance.

Answer

Verify that the scripts location in the AppSpec file is correct.

Answer

Check that the instance's IAM role has permissions to download the revision.

Question 15

A development team is using AWS CodeDeploy to deploy a web application to an Auto Scaling group. The deployment fails with a 'HealthCheck' error. The application runs on Amazon EC2 instances behind an Application Load Balancer (ALB). What is the MOST likely cause of this error?

Accepted Answer

The ALB target group health check is misconfigured or the application is not responding to health check requests.. The 'HealthCheck' error in AWS CodeDeploy indicates that the deployment failed because the target group health checks are not passing. This typically occurs when the ALB health check path or configuration does not match the application's expected response, or the application is not running correctly on the instances, causing the ALB to mark them as unhealthy. CodeDeploy monitors the ALB target group health status during deployment and will fail if instances do not become healthy within the configured timeout.

Answer

The EC2 instances do not have the correct IAM instance profile attached.

Answer

The deployment configuration is set to 'AllAtOnce' which does not support health checks.

Answer

The deployment group is not configured with the ALB target group.