DVA-C02 Deployment Practice Test 23 — 15 Questions

Question 1

A company uses AWS CodePipeline to deploy a static website to Amazon S3. The pipeline has a source stage from CodeCommit, a build stage using CodeBuild, and a deploy stage that uses S3 deployment action. The website is served via Amazon CloudFront. After a successful pipeline run, the updated files are in S3, but CloudFront still serves old content. What is the MOST efficient solution?

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

Accepted Answer

Add a post-deploy invalidation step in CodePipeline to create a CloudFront invalidation.. It automates the creation of a CloudFront invalidation as part of the CodePipeline post-deploy stage. This ensures that after new files are uploaded to S3, CloudFront's edge caches are purged of the old content, forcing it to fetch the updated files from the origin. This is the most efficient solution as it requires no manual intervention and does not compromise caching performance.

Answer

Manually create a CloudFront invalidation after each deployment.

Answer

Reduce the CloudFront distribution's default TTL to 0.

Answer

Update the S3 bucket policy to allow public read access.

Question 2

A company is deploying a containerized application on Amazon ECS using the Fargate launch type. The deployment must ensure zero downtime. Which ECS deployment configuration should be used?

Accepted Answer

Blue/green deployment using AWS CodeDeploy. Blue/green deployment using AWS CodeDeploy is correct because it creates a separate, fully functional replacement environment (green) alongside the existing one (blue), allowing traffic to be switched instantly after validation. This ensures zero downtime by avoiding in-place updates that could temporarily reduce capacity or serve errors during the transition. For ECS Fargate, CodeDeploy orchestrates the shift using an AppSpec file and can automatically roll back on health check failures.

Answer

Rolling update with a minimum healthy percent of 50% and maximum percent of 200%

Answer

Set the task placement strategy to REPLICA

Answer

Use the DAEMON scheduling strategy with a deployment circuit breaker

Question 3

Which TWO actions can be taken to enable automatic rollback for an AWS CloudFormation stack update that fails? (Select TWO.)

Accepted Answer

Specify a CloudWatch alarm in the '--rollback-configuration' parameter during stack update.. The `--rollback-configuration` parameter allows you to specify a CloudWatch alarm that, when triggered during a stack update, automatically initiates a rollback. This is the intended mechanism for monitoring-based automatic rollback, as CloudFormation will monitor the alarm state and revert the update if the alarm enters the ALARM state. Option E is correct because setting `--disable-rollback` to `false` explicitly enables automatic rollback on any stack update failure, which is the default behavior but can be explicitly configured for clarity.

Answer

Set the '--on-failure' parameter to 'ROLLBACK' during stack update.

Answer

Use a change set to review the changes before updating.

Answer

Apply a stack policy that denies updates to critical resources.

Question 4

Which THREE components are required to perform a blue/green deployment of an application running on Amazon ECS using AWS CodeDeploy? (Select THREE.)

Accepted Answer

An Application Load Balancer. An Application Load Balancer (ALB) is required for blue/green deployments on Amazon ECS with AWS CodeDeploy because it routes traffic between the 'blue' (current) and 'green' (new) task sets. CodeDeploy uses the ALB's target groups to shift traffic incrementally during the deployment, enabling zero-downtime updates. Without an ALB, there is no mechanism to direct production traffic to the new task set while keeping the old one available for rollback.

Answer

An Amazon ECS cluster

Answer

A target tracking scaling policy

Question 5

Which TWO strategies can be used to reduce the risk of a failed deployment when using AWS CodeDeploy? (Select TWO.)

Accepted Answer

Configure automatic rollback based on CloudWatch alarms.. AWS CodeDeploy can automatically trigger a rollback when a CloudWatch alarm is breached, such as when error rates or latency exceed a threshold. This reduces the risk of a failed deployment by reverting to the last known good state without manual intervention. Option B is correct because a canary deployment shifts a small percentage of traffic to the new version first, allowing you to monitor for issues before routing all traffic, minimizing blast radius.

Answer

Disable health checks to prevent false positives.

Answer

Require a manual approval step before deployment.

Answer

Deploy to all instances at once to ensure consistency.

Question 6

A developer is deploying a serverless application using the AWS Serverless Application Model (SAM). The developer runs 'sam deploy' and receives an error: 'Error: Failed to create changeset for the stack.' What is a common cause of this error?

Accepted Answer

The SAM template contains a syntax error.. The 'Failed to create changeset for the stack' error typically occurs when the SAM template contains a syntax error, such as invalid YAML formatting, missing required properties, or incorrect resource definitions. AWS CloudFormation validates the template before creating a changeset, and any syntax issue will cause the changeset creation to fail immediately. This is the most common cause because SAM templates are YAML-based and prone to indentation or structural mistakes.

Answer

The S3 bucket specified for artifacts does not exist.

Answer

The IAM user does not have permission to create CloudFormation stacks.

Answer

AWS CodeDeploy is not configured for the application.

Question 7

A company uses AWS Elastic Beanstalk to deploy a Python web application. After a successful deployment, the environment's health turns 'Severe' and the application returns HTTP 502 errors. What is the most likely cause?

Accepted Answer

The application's requirements.txt file is missing a required dependency.. A missing dependency in requirements.txt causes the Python application to fail during startup, leading to the EC2 instances reporting an unhealthy status to the Elastic Load Balancer. Elastic Beanstalk relies on the application process to respond to health checks; if the app crashes due to an ImportError, the load balancer receives no valid HTTP response and returns 502 Bad Gateway errors. The environment health turns 'Severe' because the platform detects that the application process is not running or is failing repeatedly.

Answer

The EC2 instances have insufficient storage for the deployment.

Answer

The load balancer's health check path is incorrectly configured.

Answer

The RDS database connection string is incorrect.

Question 8

A company uses AWS OpsWorks to manage a stack of EC2 instances. After a deployment, the application becomes unresponsive. The engineer suspects that a configuration file was not updated correctly. What is the best way to verify the deployed configuration?

Accepted Answer

SSH into an instance and inspect the configuration files in /var/lib/aws/opsworks.. OpsWorks stores its configuration data, including the applied custom JSON and stack settings, in /var/lib/aws/opsworks on each EC2 instance. By SSHing into the instance and inspecting these files, the engineer can directly verify whether the configuration file was updated correctly after deployment, bypassing any application-level logging or abstraction.

Answer

Use AWS Systems Manager Run Command to execute a script that outputs the configuration.

Answer

Check the OpsWorks stack's logs for any JSON syntax errors in the custom JSON.

Answer

Review the application logs in Amazon CloudWatch Logs for configuration errors.

Question 9

A team is using AWS CodePipeline with multiple stages: Source, Build, Test, and Deploy. The Deploy stage uses AWS CodeDeploy to deploy to an EC2 Auto Scaling group. The pipeline runs successfully, but the application still serves the old version. What is the most likely cause?

Accepted Answer

The CodeDeploy deployment group is associated with a different Auto Scaling group than the one serving traffic.. The most likely cause is that the CodeDeploy deployment group is associated with a different Auto Scaling group than the one actually serving traffic. Even though the pipeline runs successfully, CodeDeploy deploys the new application revision only to instances in the Auto Scaling group linked to its deployment group. If the deployment group targets a different Auto Scaling group (e.g., a staging group) while the live traffic is served by another group (e.g., production), the old version remains on the production instances.

Answer

The load balancer's target group is not pointing to the correct instances.

Answer

The build artifact in the Source stage is corrupted.

Answer

The CodeBuild stage failed silently and did not produce a new artifact.

Question 10

A developer is deploying an application using AWS CloudFormation. The stack includes an Amazon RDS DB instance. To ensure secure credential management, which TWO actions should the developer take? (Choose TWO.)

Accepted Answer

Use AWS Systems Manager Parameter Store with a SecureString parameter for the password.. AWS Systems Manager Parameter Store with a SecureString parameter is correct because it allows you to securely store the RDS master password as an encrypted parameter and reference it in the CloudFormation template using the `resolve:ssm` or `resolve:ssm-secure` dynamic reference. This avoids hardcoding the password in the template or exposing it in plaintext, while still enabling automated deployment.

Answer

Hardcode the master password in the CloudFormation template.

Answer

Use IAM database authentication to manage credentials.

Answer

Leave the master password empty so that CloudFormation generates a random password.

Question 11

A company uses CodePipeline to deploy a web application to Elastic Beanstalk. The deployment fails at the Build stage with an error 'BUILD FAILED'. Which step should the developer take first to troubleshoot?

Accepted Answer

Review the buildspec.yml file for syntax errors. The error 'BUILD FAILED' originates from the Build stage, which is executed by CodeBuild. The first step in troubleshooting a CodeBuild failure is to review the buildspec.yml file for syntax errors or misconfigurations, as this file defines the build commands, environment variables, and phases. Incorrect YAML formatting, missing required fields (e.g., 'phases'), or invalid commands will cause the build to fail immediately, making it the most direct and logical starting point.

Answer

Verify the CodeDeploy application revision

Answer

Examine the Elastic Beanstalk environment logs

Answer

Check AWS CloudTrail for API calls

Question 12

A developer is deploying a serverless application using AWS SAM. The application includes an API Gateway endpoint backed by a Lambda function. The developer wants to enable canary deployments to shift 10% of traffic to the new version for 5 minutes before routing all traffic. Which configuration should the developer add to the SAM template?

Accepted Answer

DeploymentPreference with Type: Canary10Percent5Minutes. The `DeploymentPreference` property with `Type: Canary10Percent5Minutes` instructs AWS SAM to use AWS CodeDeploy to shift 10% of traffic to the new Lambda version for 5 minutes, then automatically route the remaining 90% after the canary period ends. This matches the requirement exactly, leveraging SAM's built-in integration with CodeDeploy for canary deployments.

Answer

Add a CodeDeploy application and deployment group manually

Answer

DeploymentPreference with Type: Linear10PercentEvery1Minute

Answer

DeploymentPreference with Type: AllAtOnce

Question 13

Which THREE factors should a developer consider when choosing between a blue/green deployment and a rolling deployment for an Amazon ECS service?

Accepted Answer

Rolling deployments update a subset of tasks at a time, which may cause slower rollback. Rolling deployments in Amazon ECS update a subset of tasks at a time, which means if a rollback is needed, the deployment must reverse the updates incrementally, potentially taking longer than a blue/green deployment where traffic can be switched back instantly. This slower rollback is a key trade-off when choosing between the two strategies.

Answer

Rolling deployments require manual intervention to rollback

Answer

Blue/green deployments are always cheaper than rolling deployments

Question 14

A developer is deploying a new version of a Lambda function using the AWS CLI. The developer wants to shift 10% of traffic to the new version and then gradually increase to 100% over 10 minutes. Which CLI command should the developer use?

Accepted Answer

aws lambda update-alias --function-name my-function --name prod --function-version 2 --routing-config AdditionalVersionWeights={"1":0.9}. The `update-alias` command with the `--routing-config` parameter allows you to implement canary deployments by assigning a percentage of traffic to a new Lambda function version. In this case, `AdditionalVersionWeights={"1":0.9}` routes 10% of traffic to version 2 (the new version) and 90% to version 1. However, note that this command only sets a static routing configuration; to gradually increase traffic to 100% over 10 minutes, you must update the alias multiple times (e.g., via a script) to adjust the weights progressively. The command shown is the correct initial step to start the canary deployment.

Answer

aws lambda publish-version --function-name my-function

Answer

aws lambda create-function --function-name my-function --zip-file fileb://my-code.zip

Answer

aws lambda invoke --function-name my-function --payload '{}'

Question 15

A developer needs to deploy a containerized application on AWS. The application requires persistent storage that can be shared across multiple containers running on different EC2 instances. Which AWS service should the developer use?

Accepted Answer

Amazon Elastic File System (EFS). Amazon EFS provides a fully managed, scalable, and elastic NFS file system that can be mounted concurrently on multiple EC2 instances across different Availability Zones. This makes it the ideal choice for shared persistent storage when containers running on separate EC2 instances need to access the same data simultaneously.

Answer

Amazon S3

Answer

Amazon Elastic Block Store (EBS)

Answer

Amazon RDS