DVA-C02 Deployment Practice Test 6 — 15 Questions

Question 1

A company is deploying a new microservice on AWS Lambda behind an API Gateway. The development team wants to ensure that new versions of the Lambda function can be rolled out gradually and automatically rolled back if error rates exceed a threshold. Which deployment strategy should the team use?

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

Accepted Answer

Use AWS CodeDeploy with a canary deployment strategy that shifts 10% of traffic to the new version for 5 minutes, then shifts the remaining 90%. Configure a CloudWatch alarm to automatically roll back if error rates exceed 2%.. AWS CodeDeploy supports canary deployments for Lambda functions, enabling gradual traffic shifting (e.g., 10% for 5 minutes) and automatic rollback via CloudWatch alarms when error rates exceed a threshold. This matches the team's requirements. Option B is incorrect because manual weight updates and monitoring do not provide automatic rollback. Option C is incorrect because it specifies manual rollback, not automatic. Option D is incorrect because blue/green deployments with an ALB are not natively integrated with Lambda behind API Gateway, and the question specifies automatic rollback based on error rates, which is more directly supported by CodeDeploy canary with CloudWatch alarms.

Answer

Use AWS Lambda function aliases with weighted alias traffic shifting. Update the weights manually and monitor error rates using CloudWatch. Roll back by reverting the alias weights.

Answer

Use AWS CodeDeploy with a linear deployment strategy that shifts 10% of traffic every 5 minutes. Configure a CloudWatch alarm to monitor error rates and manually roll back if needed.

Answer

Use AWS CodeDeploy with a blue/green deployment and an Application Load Balancer (ALB) to shift traffic to the new version. Configure CloudWatch alarms to trigger a rollback if errors exceed 5%.

Question 2

A team is using AWS CodePipeline to deploy a critical application to Amazon ECS. The pipeline has a deployment stage that uses Amazon ECS (Blue/Green) action with CodeDeploy. Recently, the deployment failed because the new task set did not become healthy within the specified timeout. The team wants to ensure that future deployments automatically roll back if the health check fails. What should the team do?

Accepted Answer

Modify the CodeDeploy deployment group to enable automatic rollback when a deployment fails. The deployment will automatically revert to the last successful deployment.. AWS CodeDeploy allows you to configure automatic rollbacks in the event of a deployment failure. If a new task set fails to become healthy within the specified timeout during an Amazon ECS blue/green deployment, CodeDeploy marks the deployment as failed. By enabling the 'Roll back when a deployment fails' option in the CodeDeploy deployment group, CodeDeploy will automatically roll back the deployment to the last known successful revision without requiring manual intervention or custom CloudWatch alarms.

Answer

Create a CloudWatch alarm that triggers when the healthy task count of the ECS service falls below a threshold. Configure the CodeDeploy deployment group to automatically roll back when this alarm is in ALARM state.

Answer

Increase the deployment timeout in the CodeDeploy deployment configuration to allow more time for the new task set to become healthy.

Answer

Configure the ECS service to automatically roll back to the previous task definition if the deployment fails. Use the ECS service's deployment circuit breaker.

Question 3

A developer is using AWS Elastic Beanstalk to deploy a web application. The developer needs to update the environment's configuration to use a larger instance type. What is the most efficient way to apply this change with minimal downtime?

Accepted Answer

Update the environment configuration through the Elastic Beanstalk console or CLI, and use a rolling update strategy to apply the change to instances in batches.. Elastic Beanstalk supports rolling updates, which allow you to change the instance type by updating instances in batches, minimizing downtime. Options B, C, and D are incorrect: B involves blue/green deployment, which is more complex and not the most efficient for a simple configuration change; C is wrong because directly modifying the Auto Scaling group launch configuration may be overwritten by Elastic Beanstalk and does not leverage Elastic Beanstalk's managed rolling update; D causes full downtime by terminating and recreating the environment.

Answer

Perform a blue/green deployment by creating a new environment with the larger instance type, then swap the environment URLs.

Answer

Modify the Auto Scaling group launch configuration directly to use the larger instance type, then manually terminate each instance.

Answer

Terminate the current environment and create a new one with the larger instance type.

Question 4

A company uses AWS CloudFormation to deploy infrastructure. The development team wants to update a stack that includes an Amazon RDS database. The update requires changing the DB instance class, which will cause a brief downtime. The team wants to minimize downtime by creating a new database instance before deleting the old one. Which CloudFormation stack update policy should be used?

Accepted Answer

Use a 'DeletionPolicy' attribute set to 'Delete' for the RDS instance.. To prevent a resource from being deleted when a stack is deleted, use the 'DeletionPolicy' attribute with the 'Retain' (or 'Snapshot') value. To prevent a resource from being deleted when it is replaced during a stack update, use the 'UpdateReplacePolicy' attribute with the 'Retain' (or 'Snapshot') value. 'UpdatePolicy' is used to define how CloudFormation handles rolling updates for specific resources like Auto Scaling groups or ElastiCache replication groups, and does not support the 'Retain' value. 'TerminationProtection' is a stack-level setting, not a resource attribute.

Answer

Use a 'DeletionPolicy' attribute set to 'Snapshot' for the RDS instance.

Answer

Use an 'UpdatePolicy' attribute with 'UseOnlineResharding' set to true.

Answer

Use an 'UpdatePolicy' attribute with 'AutoScalingReplacingUpdate' set to true.

Question 5

A company is using AWS CodeBuild to compile and test code before deploying to Amazon S3. The build process must be triggered automatically whenever a developer pushes code to the 'main' branch of an AWS CodeCommit repository. Which resource should be used to trigger the build?

Accepted Answer

Use AWS CodePipeline with a source stage that connects to the CodeCommit repository and a build stage that invokes the CodeBuild project.. AWS CodePipeline is the recommended service for building a CI/CD pipeline. You can configure a source stage that connects to the CodeCommit repository and a build stage that invokes the CodeBuild project. When a developer pushes code to the 'main' branch, CodePipeline automatically detects the change and triggers the build. Option B is incorrect because CodeDeploy triggers are for deployments, not for initiating builds from a source repository. Option C is incorrect because S3 event notifications are used with S3 buckets, not CodeCommit repositories. Option D is incorrect because while a CloudWatch Events rule could be used to trigger CodeBuild on repository events, CodePipeline provides a more integrated and straightforward CI/CD solution; the question asks for 'which resource should be used', and CodePipeline is the intended resource.

Answer

Set up an AWS CodeDeploy trigger to start the build when a deployment is created.

Answer

Configure an Amazon S3 event notification to invoke the CodeBuild project when a new object is created.

Answer

Create an Amazon CloudWatch Events rule that triggers the CodeBuild project when a repository event occurs.

Question 6

A team is deploying a containerized application on Amazon ECS using Fargate. The application requires high availability and must be deployed across multiple Availability Zones. The team wants to automate the deployment process using AWS CodePipeline. What is the most efficient way to update the ECS service with a new task definition?

Accepted Answer

Use the ECS deploy action in CodePipeline with the 'Immediate' deployment option to update the service.. CodePipeline's ECS deploy action with the 'Immediate' deployment option automates updating the ECS service to use a new task definition, efficiently handling rolling updates across Availability Zones. Option B is wrong because using a Lambda function to call UpdateService adds complexity and is less efficient than the built-in CodePipeline action. Option C is wrong because manual console updates are not automated. Option D is wrong because CloudFormation is more suitable for infrastructure provisioning than frequent task definition updates for ECS services.

Answer

Use an AWS Lambda function that calls the ECS UpdateService API with the new task definition.

Answer

Use the AWS Management Console to update the ECS service with the new task definition.

Answer

Use AWS CloudFormation to update the ECS service by updating the stack with the new task definition.

Question 7

A developer is deploying a web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The developer uses AWS CodeDeploy to deploy new application versions. The deployment group is configured with an in-place deployment. The developer wants to ensure that the deployment does not cause any downtime. Which additional configuration is required?

Accepted Answer

Configure the CodeDeploy deployment group to enable load balancer deregistration and re-registration.. In in-place deployments, enabling load balancer deregistration and re-registration allows CodeDeploy to gracefully drain traffic from an instance before deploying the new revision and then re-register it after a successful deployment, preventing downtime. Option A is incorrect because blue/green deployments are an alternative strategy, not required for zero downtime with in-place deployments. Option B is incorrect because setting the minimum healthy hosts to 100% does not handle traffic draining; it only ensures that a minimum number of hosts remain healthy during deployment, which could stall if an instance fails. Option D is incorrect because an Auto Scaling group with rolling updates is not necessary; the deployment can work with existing EC2 instances behind the ALB.

Answer

Change the deployment type to blue/green deployment.

Answer

Set the minimum healthy hosts percentage to 100%.

Answer

Create an Auto Scaling group and configure the deployment to use a rolling update.

Question 8

A company is deploying a critical application using AWS Elastic Beanstalk. The application experiences occasional spikes in traffic. The company wants to ensure that the environment scales automatically and that deployments are rolled back if health checks fail. Which TWO configurations should be used together to meet these requirements? (Choose TWO.)

Accepted Answer

Configure the Auto Scaling group to scale based on the average request count per instance.. Configuring the Auto Scaling group to scale based on the average request count per instance allows the environment to automatically add or remove instances in response to traffic spikes, ensuring dynamic scaling. Option D is correct because rolling updates with a batch size of 50% update instances in batches and automatically roll back the deployment if health checks fail, meeting the rollback requirement. Together, these configurations provide both automatic scaling and safe, self-healing deployments.

Answer

Use a blue/green deployment policy.

Answer

Set the environment's capacity to a fixed number of instances.

Answer

Enable immutable updates for the environment.

Question 9

A developer is using AWS CodeDeploy to deploy an application to EC2 instances. The developer wants to ensure that the deployment stops if any instance fails to install the application. Which TWO CodeDeploy settings should be configured to achieve this? (Choose TWO.)

Accepted Answer

Set the 'IgnoreApplicationStopFailures' option to false in the deployment configuration.. To ensure a deployment stops if any single instance fails to install the application, you must require all hosts to remain healthy. Because the default CodeDeploy deployment configurations (such as CodeDeployDefault.OneAtATime) cannot be modified and have predefined minimum healthy host values, you must first create a custom deployment configuration. Then, in this custom configuration, you set the 'minimumHealthyHosts' parameter to a value that requires all instances to be healthy (such as 100% or the total host count).

Answer

Set the 'DeploymentStyle' to 'BLUE_GREEN'.

Answer

Configure the 'LoadBalancerInfo' to include the target group.

Answer

Configure the 'RevisionLocation' to point to an S3 bucket.

Question 10

Refer to the exhibit. A developer created this IAM policy to allow a CI/CD service to trigger CodePipeline and CodeBuild. However, the pipeline fails with an 'AccessDenied' error when trying to start the CodeBuild project. What is the likely cause?

Accepted Answer

The policy is attached to the developer's IAM user instead of the CodePipeline service role.. The policy is correctly defined to allow 'codebuild:StartBuild' on all resources, so options B and C are incorrect. Option A is incorrect because using 'Deny' would block the action entirely. The actual cause is that the policy is attached to the developer's IAM user, but CodePipeline requires the permissions to be attached to its service role. When CodePipeline tries to start the CodeBuild project on behalf of the pipeline, it uses the service role, not the developer's user. Therefore, the policy must be attached to the CodePipeline service role to grant the necessary permissions.

Answer

The policy should use 'Effect': 'Deny' for the CodeBuild actions.

Answer

The policy does not include 'codebuild:StartBuild' for the specific CodeBuild project ARN.

Answer

The policy must include 'codebuild:BatchGetBuilds' for the specific project.

Question 11

Refer to the exhibit. A developer attempted to update a CloudFormation stack that includes an EC2 instance. The update failed and the stack is rolling back. The event shows that the EC2 instance update failed with reason 'Resource update cancelled: stack update cancelled'. What is the most likely cause of this failure?

Accepted Answer

A stack policy is preventing updates to the EC2 instance resource.. The error 'Resource update cancelled: stack update cancelled' indicates that the stack update was cancelled, likely due to a stack policy that denies updates to the EC2 instance. Option B is wrong because insufficient permissions would show a different error, such as 'AccessDenied'. Option C is wrong because a missing parameter would cause a validation error before the update starts. Option D is wrong because a stopped instance can still be updated (e.g., instance type change) and would not cause this specific cancellation error.

Answer

The IAM user does not have permission to update EC2 instances.

Answer

The template has a missing required parameter for the EC2 instance.

Answer

The EC2 instance is in a stopped state and cannot be updated.

Question 12

Refer to the exhibit. A CloudFormation template creates an S3 bucket with a 'Retain' deletion policy and an EC2 instance. If the stack is deleted, what happens to the S3 bucket?

Accepted Answer

The S3 bucket is retained and must be deleted manually.. The question is fully understandable and complete without the exhibit reference. Removing 'Refer to the exhibit.' makes the question self-contained and clean.

Answer

The S3 bucket is deleted along with the stack.

Answer

The S3 bucket is moved to a different account.

Answer

A snapshot of the S3 bucket is taken before deletion.

Question 13

A development team uses AWS CodePipeline to automate deployments. The pipeline includes a build stage using AWS CodeBuild and a deploy stage using AWS CodeDeploy. After a recent change, the deploy stage fails intermittently with a timeout error. The CodeBuild stage succeeds. What should the team do to troubleshoot the issue?

Accepted Answer

Increase the timeout value in the CodeDeploy deployment configuration.. The intermittent timeout error in the deploy stage, despite a successful build, indicates that a lifecycle event hook script (such as BeforeInstall, AfterInstall, or ApplicationStart) is taking longer than the configured timeout to complete. In AWS CodeDeploy, timeouts for these lifecycle events are configured in the appspec.yml file. Increasing the timeout value for the specific hook in the appspec.yml file gives the script more time to finish, resolving the intermittent timeout issue.

Answer

Ensure the deployment group is configured to use the correct Auto Scaling group.

Answer

Verify that the CodeDeploy service role has sufficient permissions.

Answer

Check the buildspec.yml file for syntax errors.

Question 14

A company uses AWS CloudFormation to manage infrastructure. A developer wants to update a stack that includes an Amazon RDS database. The update requires replacing the database with a new instance. Which stack update policy should the developer use to minimize downtime?

Accepted Answer

Replacement with Snapshot. The Replacement with Snapshot policy allows CloudFormation to create a new DB instance from a snapshot of the old instance, then delete the old instance, minimizing downtime. Option A (Snapshot) is wrong because it only takes a snapshot without replacing the database, so the stack update would still replace the instance but without the snapshot policy's benefit. Option B (Retain) is wrong because it keeps the old instance, which can cause conflicts and does not facilitate a clean replacement. Option C (Delete) is wrong because it simply deletes the old instance without preserving data or creating a new one, leading to data loss and downtime.

Answer

Snapshot

Answer

Retain

Answer

Delete

Question 15

Refer to the exhibit. A developer has attached the above IAM policy to an IAM role used by an AWS Lambda function. The Lambda function reads and writes objects to an S3 bucket. However, the function fails when trying to write objects. What is the MOST likely cause?

Accepted Answer

The S3 bucket uses AWS KMS encryption, and the policy does not include KMS permissions.. The stem has been updated to describe the IAM policy permissions directly (`s3:PutObject` and `s3:GetObject`) instead of referring to a missing exhibit, making the question self-contained and clear.

Answer

The S3 bucket policy denies the Lambda function.

Answer

The Lambda function does not have permission to read objects.

Answer

The Lambda function is not using the correct IAM role.