DVA-C02 Practice Exam 68 — 20 Questions

Question 1

A developer is using AWS CodeDeploy to deploy an application to an EC2 Auto Scaling group. The developer wants to monitor the deployment and automatically roll back if a specified Amazon CloudWatch alarm is triggered during the deployment. Which CodeDeploy feature should the developer configure?

Accepted Answer

Deployment group alarm configuration. The Deployment group alarm configuration in AWS CodeDeploy allows you to specify Amazon CloudWatch alarms that, when triggered during a deployment, automatically initiate a rollback. This feature is configured at the deployment group level and ensures that if a predefined alarm (e.g., high error rate or latency) enters the ALARM state, CodeDeploy stops the deployment and reverts to the last known good revision. This provides automated, policy-driven rollback without manual intervention.

Answer

Deployment configuration with alarm

Answer

Revision rollback

Answer

EC2 instance health check

Question 2

A developer is using AWS CodePipeline to deploy a web application. The pipeline has a source stage that pulls from CodeCommit and a deploy stage that uses AWS Elastic Beanstalk. The developer wants to run unit tests automatically before deploying to Elastic Beanstalk. Which action should the developer add to the pipeline?

Accepted Answer

Add a test stage that uses an AWS CodeBuild project configured to run unit tests. Option A is correct because AWS CodeBuild can be integrated as a test stage in CodePipeline to run unit tests automatically. By adding a CodeBuild project configured with a buildspec.yml file that executes unit tests, the pipeline will run tests after the source stage and before the deploy stage, ensuring only code that passes tests is deployed to Elastic Beanstalk.

Answer

Add a manual approval step before the deploy stage

Answer

Configure Elastic Beanstalk health checks to run tests

Answer

Replace Elastic Beanstalk with AWS CodeDeploy

Question 3

Drag and drop the steps to create a Lambda function that processes S3 events in the correct order.

Question 4

A developer is using AWS CodeDeploy with a blue/green deployment strategy to update an application running on Amazon ECS with the Fargate launch type. After the new (green) task set is created and traffic is shifted to it, users immediately report errors when trying to write data. The developer discovers that the green task set is connecting to a different database than the blue task set. The database endpoints are configured in the ECS task definition. What is the simplest way to prevent this issue in future deployments?

Accepted Answer

Modify the blue/green deployment configuration to use the same database endpoint for both task sets by updating the environment variables in the task definition before deployment.. Option A is correct because the issue stems from the green task set using a different database endpoint than the blue task set, which is configured via environment variables in the ECS task definition. By updating the task definition to use the same database endpoint before deployment, both task sets will connect to the same database, ensuring consistency during the traffic shift. This is the simplest fix as it requires no additional infrastructure or complex routing changes.

Answer

Create two separate Amazon RDS databases and use an Amazon Route 53 weighted routing policy to distribute traffic.

Answer

Use an Application Load Balancer (ALB) with stickiness to route each user to the correct task set.

Answer

Use AWS CloudFormation to create a new database stack for each deployment and update the task definition dynamically.

Question 5

A developer wants to deploy a new version of an application to an EC2 Auto Scaling group using AWS CodeDeploy. The developer wants to minimize downtime and ensure that if the deployment fails, it automatically rolls back to the previous version. Which deployment type should the developer choose?

Accepted Answer

Blue/green. Blue/green deployment is the correct choice because it creates a separate, new Auto Scaling group (green) alongside the existing one (blue), allowing traffic to be shifted to the new environment after validation. This minimizes downtime by keeping the old environment fully operational during the deployment, and CodeDeploy can automatically roll back by redirecting traffic to the blue environment if the deployment fails.

Answer

In-place

Answer

Canary

Answer

Linear

Question 6

Match each HTTP status code to its meaning.

Question 7

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

Question 8

A CodeDeploy deployment to Lambda should shift 10 percent of traffic for 10 minutes before full rollout and automatically roll back on alarms. Which configuration should be used?

Accepted Answer

Canary deployment preference with CloudWatch alarms. A is correct because CodeDeploy's canary deployment preference shifts 10% of traffic to the new Lambda version for 10 minutes, then automatically shifts the remaining 90% after the specified interval. CloudWatch alarms are configured to trigger an automatic rollback if the alarm state is breached during the canary period, meeting the requirement for a gradual shift with automated rollback on failure.

Answer

All-at-once deployment without alarms

Answer

Manual alias update after deployment

Answer

S3 static website deployment

Question 9

A developer is using AWS CodeDeploy to deploy an application to an Auto Scaling group of EC2 instances. The developer wants to minimize the number of instances that are taken out of service at any given time during the deployment. Which predefined deployment configuration should the developer use?

Accepted Answer

OneAtATime. The OneAtATime deployment configuration shifts traffic to one new instance at a time, ensuring that only a single instance is taken out of service during the deployment. This minimizes the number of instances removed from the Auto Scaling group at any given moment, which directly meets the developer's requirement to reduce service disruption.

Answer

AllAtOnce

Answer

HalfAtATime

Answer

Custom with 50% at a time

Question 10

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

Question 11

A developer is using the AWS Serverless Application Model (SAM) to define a serverless application with an API Gateway endpoint. The developer wants to enable API caching only in the development stage to speed up testing, but disable it in the production stage to ensure data freshness. What is the most efficient way to achieve this with SAM?

Accepted Answer

Use AWS SAM parameters with a condition to set CacheClusterEnabled based on the stage parameter.. AWS SAM parameters allow you to define a stage parameter (e.g., 'dev' or 'prod') and use a condition to conditionally set the `CacheClusterEnabled` property on the `AWS::Serverless::Api` resource. This is the most efficient approach because it uses a single template and SAM's built-in intrinsic functions (like `Fn::Equals`) to toggle caching based on the deployment stage, avoiding separate templates or post-deployment custom resources.

Answer

Deploy two separate SAM templates, one for each stage.

Answer

Use a custom resource to toggle caching after deployment.

Answer

Enable caching globally and configure a usage plan with a quota for production.

Question 12

A developer is building a serverless application using AWS SAM that includes an API Gateway REST API and a Lambda function. The developer wants to pass environment variables to the Lambda function based on the deployment stage (dev/prod). The stage name is provided as a SAM parameter. How should the developer define this in the SAM template?

Accepted Answer

Define a SAM Parameter for the stage name, and reference it in the Lambda function's Environment property. Option A is correct because AWS SAM allows you to define parameters (e.g., StageName) and reference them directly in the Lambda function's Environment property using CloudFormation intrinsic functions like !Ref. This enables dynamic injection of environment variables based on the deployment stage without modifying the template structure, aligning with Infrastructure as Code best practices for multi-environment deployments.

Answer

Use the Globals section of the SAM template to set environment variables

Answer

Hard-code the environment variables with different values in the template

Answer

Use an AWS Systems Manager Parameter Store parameter and reference it in the function

Question 13

A developer is building a serverless application using AWS SAM. The application includes an Amazon API Gateway endpoint with a Lambda function that processes user uploads. The developer wants to enable API caching in the development stage to speed up repeated requests, but disable caching in the production stage. What is the most efficient way to achieve this?

Accepted Answer

Configure caching in the SAM template using the CacheClusterEnabled property and use CloudFormation conditions to enable it only in the dev stage.. Option A is correct because AWS SAM extends AWS CloudFormation, allowing you to use CloudFormation conditions to conditionally enable the `CacheClusterEnabled` property on the `AWS::ApiGateway::Stage` resource. By defining a condition that evaluates to true only for the dev stage (e.g., based on a parameter like `StageName`), you can enable caching in dev and disable it in prod within a single SAM template, avoiding duplication and manual steps.

Answer

Create two separate SAM templates, one for dev with caching and one for prod without.

Answer

Enable caching in the API Gateway console after each deployment for the dev stage.

Answer

Use a custom CloudFormation resource to toggle caching based on a parameter.

Question 14

A developer is using AWS X-Ray to trace a serverless application. The application uses an AWS Lambda function to query a DynamoDB table. The trace shows that the DynamoDB subsegment takes a significant portion of the total response time. The developer wants to reduce the DynamoDB query latency. Which service should the developer integrate with the Lambda function to achieve the lowest latency for repeated read queries?

Accepted Answer

DynamoDB Accelerator (DAX). DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache for DynamoDB that delivers up to 10x read performance improvement by reducing response times from milliseconds to microseconds for repeated read queries. By integrating DAX with the Lambda function, the developer can cache the results of frequent DynamoDB queries directly in memory, bypassing the read capacity units and the underlying storage engine, which directly addresses the latency bottleneck shown in the X-Ray trace.

Answer

Amazon ElastiCache for Redis

Answer

DynamoDB Global Tables

Answer

DynamoDB Streams

Question 15

Drag and drop the steps to encrypt an EBS volume using AWS KMS in the correct order.

Question 16

A developer is storing application configuration data in DynamoDB. The data is frequently accessed by partition key, and items are small (less than 1KB). The read traffic is consistent and predictable. Which read capacity mode is most cost-effective for this workload?

Accepted Answer

Provisioned with fixed capacity. Provisioned with fixed capacity is the most cost-effective option for this workload because the read traffic is consistent and predictable, and items are small (less than 1KB). With fixed provisioned capacity, you pay a flat hourly rate for a set number of read capacity units (RCUs), avoiding the per-request premium of on-demand mode or the overhead of auto scaling. Since the workload does not require elasticity, fixed capacity minimizes cost while ensuring sufficient throughput.

Answer

On-demand

Answer

Provisioned with auto scaling

Answer

Provisioned with reserved capacity

Question 17

A developer wants to store session state data for a web application running on multiple EC2 instances behind an Application Load Balancer. The data is ephemeral and should not persist if an instance is terminated. Which storage option should the developer use?

Accepted Answer

Amazon ElastiCache. Amazon ElastiCache is the correct choice because it provides an in-memory caching service (e.g., Redis or Memcached) that is ideal for storing ephemeral session state data. The data is stored in memory, not on disk, so it is automatically lost when an EC2 instance is terminated, matching the requirement that session data should not persist. Additionally, ElastiCache is designed for low-latency access, making it suitable for session state that must be quickly read and written by multiple instances behind an Application Load Balancer.

Answer

Amazon RDS

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Amazon S3

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Amazon EFS

Question 18

A developer must locally test a SAM-based Lambda function with an API event before deployment. Which tool command family is designed for this?

Accepted Answer

AWS SAM CLI local invoke/start-api. The AWS SAM CLI provides the `local invoke` and `local start-api` commands specifically for testing Lambda functions locally with simulated API Gateway events before deployment. `sam local start-api` creates a local HTTP server that mimics API Gateway, allowing developers to send requests to their Lambda functions as if they were deployed, while `sam local invoke` directly invokes the function with a specified event payload. This is the only tool family designed for local testing of SAM-based Lambda functions with API events.

Answer

AWS Shield Advanced CLI

Answer

AWS Organizations policy simulator

Answer

Amazon Inspector SBOM export

Question 19

A developer wants a Lambda function to process SQS messages in batches but avoid losing the whole batch when only one record fails. Which feature should be enabled?

Accepted Answer

Partial batch response for SQS event source mapping. Partial batch response for SQS event source mapping allows the Lambda function to report which messages in a batch failed processing. When enabled, Lambda retries only the failed messages instead of the entire batch, preventing successful messages from being reprocessed or lost. This is achieved by returning a `batchItemFailures` array in the function's response, which tells Lambda which message IDs to retry.

Answer

Reserved concurrency of one

Answer

Maximum message size increase

Answer

SQS short polling

Question 20

A developer is building a REST API using Amazon API Gateway and wants to transform the request data before sending it to the backend Lambda function. The transformation includes mapping query string parameters to a JSON body. Which API Gateway feature should be used?

Accepted Answer

Velocity Template Language (VTL) mapping templates. Option A is correct because API Gateway uses Velocity Template Language (VTL) mapping templates to transform incoming request data, such as mapping query string parameters into a JSON body before passing it to the backend Lambda function. This feature allows you to define a template that extracts values from the request's query string parameters (e.g., `$input.params('paramName')`) and constructs a new JSON payload, enabling seamless integration with Lambda without modifying the client request.

Answer

Lambda authorizer

Answer

Request validator

Answer

CORS configuration