DVA-C02 Deployment Practice Test 18 — 15 Questions

Question 1

A SAM application should gradually shift Lambda traffic and roll back on errors. Which two pieces are needed?

Accepted Answer

A Lambda alias/deployment preference. AWS SAM uses Lambda aliases with deployment preferences (e.g., Canary10Percent5Minutes or Linear10PercentEvery10Minutes) to gradually shift traffic from the old version to the new version. Option C is correct because CloudWatch alarms can be tied to the deployment preferences to automatically roll back the traffic shift if the alarm enters the ALARM state, indicating errors or degraded health.

Answer

An S3 lifecycle rule

Answer

A public S3 bucket

Question 2

Drag and drop the steps to set up a custom domain for an API Gateway API in the correct order.

Accepted Answer

1. Register or have a domain, 2. Request or import a certificate in ACM, 3. Create a custom domain name in API Gateway, 4. Create an API mapping to a stage, 5. Update DNS records to point to the API Gateway domain name. First have a domain, get a certificate, create custom domain in API Gateway, map to stage, and update DNS.

Answer

1. Create a custom domain name in API Gateway, 2. Register or have a domain, 3. Request or import a certificate in ACM, 4. Create an API mapping to a stage, 5. Update DNS records

Answer

1. Update DNS records, 2. Register or have a domain, 3. Request or import a certificate in ACM, 4. Create a custom domain name in API Gateway, 5. Create an API mapping to a stage

Answer

1. Register or have a domain, 2. Create a custom domain name in API Gateway, 3. Request or import a certificate in ACM, 4. Create an API mapping to a stage, 5. Update DNS records

Question 3

Match each HTTP status code to its meaning.

Accepted Answer

200: OK. Correct matches: 200 OK, 404 Not Found, 500 Internal Server Error. Common confusions include mixing 200 and 201, or 404 and 403.

Answer

200: Created

Answer

404: Forbidden

Question 4

Match each AWS service to its port number (if applicable).

Accepted Answer

Amazon RDS (MySQL engine): 3306. Default ports are important for configuring security groups and connecting to databases.

Answer

Amazon RDS (MySQL engine): 5439

Answer

Amazon Redshift: 3306

Question 5

A company uses AWS CodeDeploy to deploy a web application to an Auto Scaling group. The deployment fails with the error 'The overall deployment failed because too many individual instances failed deployment'. The deployment configuration is set to CodeDeployDefault.OneAtATime. What is the most likely cause of this failure?

Accepted Answer

The deployment failed on a single instance, causing the overall deployment to fail because the minimum number of healthy hosts was not maintained.. CodeDeployDefault.OneAtATime deploys to one instance at a time. The deployment stops immediately if a single instance fails, because the deployment configuration expects no failures. The error 'too many individual instances failed' is triggered by that single failure, since the deployment cannot proceed to the next instance without violating the minimum healthy hosts requirement, which is set to maintain availability.

Answer

The instances in the Auto Scaling group are not running a supported operating system.

Answer

The deployment configuration should be changed to AllAtOnce to avoid this error.

Answer

The IAM role for CodeDeploy does not have sufficient permissions.

Question 6

A developer is using AWS Elastic Beanstalk to deploy a Node.js application. The developer wants to run a custom script to set environment variables before the application starts. Which configuration file and location should the developer use?

Accepted Answer

Add a configuration file in the .ebextensions directory that uses container_commands.. `.ebextensions` configuration files with `container_commands` allow you to run custom commands before the application starts. `container_commands` execute after the application and web server have been set up but before the application is deployed, making them ideal for setting environment variables or running setup scripts. The files must be in YAML or JSON format and placed in the `.ebextensions` directory at the root of your source bundle.

Answer

Add a Procfile to the application root.

Answer

Place a shell script in the .ebextensions/scripts directory.

Answer

Add a cron.yaml file to the .ebextensions directory.

Question 7

A company is using AWS CodeDeploy with an in-place deployment to an Auto Scaling group. The deployment fails with the error 'Deployment failed because the deployment group does not have enough instances to deploy to'. The Auto Scaling group has a minimum size of 2, maximum size of 5, and desired capacity of 2. The deployment configuration is CodeDeployDefault.AllAtOnce. What is the most likely cause?

Accepted Answer

The instances in the Auto Scaling group are not passing health checks.. The error 'Deployment failed because the deployment group does not have enough instances to deploy to' occurs when there are zero healthy instances in the deployment group at the start of deployment. With CodeDeployDefault.AllAtOnce, the minimum number of healthy hosts is 0, so a single instance failure during deployment would not trigger this error. The most likely cause is that the instances in the Auto Scaling group are not passing health checks, resulting in no healthy instances available for deployment. Option C is correct.

Answer

The Auto Scaling group needs to have at least 3 instances to use AllAtOnce.

Answer

The deployment configuration is not compatible with Auto Scaling groups.

Answer

The deployment group has only 2 instances, and the deployment failed on one instance, causing the minimum healthy hosts threshold to be violated.

Question 8

A developer is deploying a Docker container to Amazon ECS using the Fargate launch type. The developer wants to ensure the container has access to an Amazon RDS database. What is the best way to securely pass the database credentials to the container?

Accepted Answer

Use AWS Systems Manager Parameter Store or AWS Secrets Manager to store the credentials and reference them in the task definition.. AWS Systems Manager Parameter Store and AWS Secrets Manager are designed to securely store and manage sensitive information like database credentials. In Amazon ECS with Fargate, you can reference these secrets directly in the task definition using the 'secrets' parameter, which injects them as environment variables at runtime without exposing them in plain text or requiring additional code to fetch them. This approach adheres to the principle of least privilege and integrates natively with IAM roles for secure access.

Answer

Pass the credentials as plain text environment variables in the task definition.

Answer

Store the credentials in an Amazon S3 bucket and download them at container startup.

Answer

Store the credentials in the container image as environment variables.

Question 9

A developer is using AWS CodeBuild to build a Java application. The build fails with the error 'BUILD_CONTAINER_UNABLE_TO_PULL_IMAGE'. What is the most likely cause?

Accepted Answer

The Docker image specified in the build environment does not exist or the repository is not accessible.. The error 'BUILD_CONTAINER_UNABLE_TO_PULL_IMAGE' in AWS CodeBuild indicates that the service cannot pull the specified Docker image from the repository. This occurs when the image name/tag is incorrect, the image does not exist in the specified registry (e.g., Amazon ECR or Docker Hub), or the CodeBuild service role lacks the necessary permissions (e.g., ecr:GetDownloadUrlForLayer, ecr:BatchGetImage) to access the repository. Option B correctly identifies this as the most likely cause.

Answer

The build environment does not have enough memory.

Answer

The build command has a syntax error.

Answer

The buildspec.yml file does not define artifacts.

Question 10

A company is using AWS CloudFormation to manage infrastructure. The developer wants to update a stack but needs to prevent specific resources from being replaced. What CloudFormation feature should the developer use?

Accepted Answer

Apply a stack policy that denies updates to the specific resources.. A stack policy is a JSON-based policy that defines which resources in a CloudFormation stack can be updated, replaced, or deleted. By applying a stack policy that denies updates to specific resources, the developer can prevent those resources from being replaced during a stack update, even if the template change would normally trigger a replacement.

Answer

Use a custom resource to manage the update logic.

Answer

Create a change set to review the changes before execution.

Answer

Use a deletion policy attribute on the resources to protect them.

Question 11

A developer is deploying a static website to Amazon S3 and wants to use Amazon CloudFront for content delivery. The developer wants to ensure that only CloudFront can access the S3 bucket. Which S3 bucket policy should the developer use?

Accepted Answer

Grant CloudFront access via an origin access identity (OAI) and restrict the bucket policy to the OAI.. An Origin Access Identity (OAI) is a special CloudFront user that you can associate with your distribution. By configuring the S3 bucket policy to grant access only to that OAI, you ensure that direct S3 requests are denied, and only requests routed through CloudFront can retrieve objects. This provides a secure, private origin without exposing the bucket publicly.

Answer

Use a bucket policy that allows access only if the Referer header matches the CloudFront distribution domain.

Answer

Make the bucket public and use CloudFront's default caching.

Answer

Grant CloudFront access by allowing the CloudFront IP address range.

Question 12

A company is deploying a microservices architecture using AWS Lambda and Amazon API Gateway. The developer wants to implement a canary release deployment for the API. Which THREE steps should the developer take? (Choose THREE.)

Accepted Answer

Configure stage variables to point the canary stage to a different Lambda function alias.. Stage variables in API Gateway can be configured to point the canary stage to a different Lambda function alias, enabling the canary to invoke a separate version of the function for testing. This allows the canary to route a percentage of traffic to a new Lambda version while the main stage continues using the stable alias, supporting gradual rollouts.

Answer

Use Amazon CloudFront to distribute traffic between two API Gateway stages.

Answer

Use Lambda canary releases to gradually shift traffic.

Question 13

A company is deploying a new microservice on AWS Lambda that processes high-resolution images and stores results in Amazon S3. The Lambda function currently uses 1024 MB of memory and has a timeout of 2 minutes. During peak load, many invocations are timing out. The function is CPU-bound during image processing. Which change is MOST likely to reduce timeouts without increasing costs unnecessarily?

Accepted Answer

Increase the function memory to 2048 MB.. Increasing memory from 1024 MB to 2048 MB proportionally increases CPU allocation in AWS Lambda (up to 1.7 GHz per vCPU at 1769 MB). Since the function is CPU-bound, this directly reduces processing time, mitigating timeouts without the cost spike of 3008 MB. The cost increase is linear with memory, so doubling memory doubles cost per invocation, but the reduced duration often offsets this, keeping total cost similar or lower.

Answer

Increase the function memory to 3008 MB.

Answer

Enable provisioned concurrency to reduce cold starts.

Answer

Increase the function timeout to 5 minutes.

Question 14

An e-commerce platform uses AWS CodePipeline to deploy a web application to an Auto Scaling group behind an Application Load Balancer. The deployment strategy must minimize downtime and allow immediate rollback if the new version fails health checks. Which deployment configuration meets these requirements?

Accepted Answer

Use blue/green deployment with an immutable infrastructure.. Blue/green deployment with immutable infrastructure minimizes downtime by running the new version (green) alongside the old (blue) and switching traffic only after health checks pass. If the new version fails, rollback is immediate by routing traffic back to the blue environment without redeploying. AWS CodePipeline supports this via CodeDeploy with a blue/green configuration, ensuring zero-downtime deployments and instant rollback capability.

Answer

Use all-at-once deployment to the Auto Scaling group.

Answer

Use canary deployment shifting 10% traffic for 5 minutes.

Answer

Use in-place rolling update with a batch size of 50%.

Question 15

A company uses AWS CloudFormation to manage infrastructure. The development team wants to deploy a new version of a Lambda function without downtime. The function is part of a stack. Which action should the team take?

Accepted Answer

Update the CloudFormation stack with the new function code and deploy the stack update.. Updating the CloudFormation stack with the new Lambda function code and deploying the stack update is the correct approach because CloudFormation performs a rolling update on the Lambda function, replacing the old version with the new one without deleting the stack. This ensures zero downtime as the update is applied in place, and the function remains available throughout the process.

Answer

Create a change set and execute it after the current stack is deleted.

Answer

Manually update the Lambda function code in the console and then update the stack.

Answer

Create a new CloudFormation stack for the new function and delete the old stack.