DVA-C02 Practice Exam 52 — 20 Questions

Question 1

A company uses AWS CloudFormation to manage infrastructure. A developer wants to update a stack but needs to ensure that certain resources are not accidentally deleted. The developer wants to protect specific resources from stack updates that would delete them. Which CloudFormation feature should the developer use?

Accepted Answer

Set the DeletionPolicy attribute to Retain on the resources. Option C is correct because termination protection prevents a stack from being deleted, but not individual resources. Stack policy controls which resources can be updated or deleted. Option A is incorrect because a stack policy can protect resources. Option B is incorrect because a Change Set shows changes but does not prevent deletion. Option D is incorrect because DeletionPolicy is a resource attribute that can preserve resources, but it is set at resource level, not during update.

Answer

Enable termination protection on the stack

Answer

Use a Change Set to review changes before applying them

Answer

Use a stack policy to prevent deletion of specific resources

Question 2

A developer is using AWS CodePipeline to automate deployments. The pipeline has a source stage that pulls code from an Amazon S3 bucket. Which TWO actions can the developer take to automatically start the pipeline when new code is uploaded to the S3 bucket? (Choose TWO.)

Accepted Answer

Use Amazon CloudWatch Events to listen for S3 PutObject events and target the pipeline. Options A and D are correct. S3 events can trigger Lambda or directly start a pipeline via CloudWatch Events. Option B is incorrect because CodeBuild is used for build, not trigger. Option C is incorrect because SQS is not a direct trigger for CodePipeline. Option E is incorrect because polling is not automatic.

Answer

Configure the pipeline to use a periodic poll of the S3 bucket

Answer

Configure an S3 event notification to trigger an AWS CodeBuild build

Answer

Configure the S3 bucket to send events to an Amazon SQS queue, and configure the pipeline to poll the queue

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.. Option C is correct because Elastic Beanstalk supports rolling updates and rolling deployments that can update the instance type without downtime by updating instances in batches. Option A is wrong because terminating and recreating causes downtime. Option B is wrong because Blue/green deployment requires creating a new environment and swapping URLs, which is more effort. Option D is wrong because modifying the Auto Scaling group directly is not recommended as Elastic Beanstalk manages the resources; changes may be overwritten.

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 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.. Option B is correct because using a load balancer with in-place deployment, CodeDeploy can register instances with the load balancer and deregister them before deployment, then re-register after. This minimizes downtime. Option A is wrong because creating an Auto Scaling group is not necessary; the deployment can work with existing instances. Option C is wrong because using blue/green deployment is an alternative, but the question specifically asks for in-place. Option D is wrong because increasing the minimum healthy hosts percentage helps but does not eliminate downtime if instances are not properly drained.

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 5

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. Option C is correct because the Replacement policy with Snapshot allows CloudFormation to create a new DB instance, take a snapshot of the old instance, and then delete the old instance, minimizing downtime. Option A is wrong because Delete does not preserve data. Option B is wrong because Retain keeps the old instance, causing downtime. Option D is wrong because Snapshot without Replacement is not a valid update policy.

Answer

Snapshot

Answer

Retain

Answer

Delete

Question 6

A company uses AWS CodeDeploy to deploy a web application to an Auto Scaling group. The deployment fails during the BeforeInstall lifecycle event. What should the developer do to troubleshoot the issue?

Accepted Answer

Check the appspec.yml file for errors in the BeforeInstall hook.. Option D is correct because the BeforeInstall hook scripts are in the appspec.yml file. Option A is wrong because the deployment group configuration is not the issue. Option B is wrong because the build output is already successful. Option C is wrong because the deployment configuration settings are not related.

Answer

Check the deployment group configuration.

Answer

Verify the build output from CodeBuild.

Answer

Review the deployment configuration settings.

Question 7

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.. Option B is correct because the policy allows 'codebuild:StartBuild' on all resources, but CodePipeline needs to start builds on behalf of the pipeline. The CodeBuild project resource ARN is not specified; however, the 'Resource' is '*', so that should be fine. Actually, the issue might be that the policy allows StartBuild for CodeBuild, but the pipeline's service role needs permissions. The policy shown is for a user, not for the pipeline's service role. The question says 'a developer created this IAM policy', but the pipeline uses a service role. So the correct answer is that the policy should be attached to the pipeline's service role, not the developer. Option A is wrong because the action is correct. Option C is wrong because the resource is '*', covering all projects. Option D is wrong because the policy does not need to be attached to the user; it needs to be attached to the pipeline's role.

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 8

A developer is using AWS CloudFormation to manage infrastructure. The developer needs to update a stack that contains a resource that requires replacement. Which TWO actions can the developer take to perform the update with minimal downtime?

Accepted Answer

Create a new stack with the updated resource and then update the DNS to point to the new stack.. Options A and D are correct because creating a new stack in parallel and using a blue/green deployment with CodeDeploy minimize downtime. Option B causes downtime. Option C is not a method. Option E does not address downtime.

Answer

Use a change set and execute it, allowing CloudFormation to replace the resource.

Answer

Use the 'Stack Policy' to prevent replacement.

Answer

Delete the stack and recreate it.

Question 9

A company is deploying a critical application using AWS CodeDeploy. To minimize downtime, they want to perform a blue/green deployment. Which TWO strategies should they implement?

Accepted Answer

Create an Elastic Load Balancer to route traffic between the blue and green environments.. Option B (use an Elastic Load Balancer) is correct because blue/green deployments require traffic switching between environments. Option D (register instances with the ELB) is correct because the new instance group must be registered to receive traffic. Option A is wrong because a 'swap' is not a standard approach. Option C is wrong because DNS changes are not typically used with CodeDeploy. Option E is wrong because CodeDeploy does not support A/B testing natively.

Answer

Use an Amazon Route 53 weighted routing policy to gradually shift traffic.

Answer

Configure an AWS Lambda function to perform A/B testing during deployment.

Answer

Use an Amazon CloudFront distribution with multiple origins.

Question 10

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.. Option B is correct because 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 A is wrong because insufficient permissions would show a different error. Option C is wrong because the instance being in a stopped state would cause a different error. Option D is wrong because a missing parameter would cause a validation error before update.

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 11

A company deploys a critical application on Amazon ECS with Fargate using a blue/green deployment strategy with AWS CodeDeploy. The deployment group has two target groups, one for blue and one for green. The Application Load Balancer (ALB) is configured with a listener that forwards traffic to the blue target group initially. A recent deployment to the green environment failed, and the green service is in a steady state with zero healthy tasks. The developer needs to ensure that the blue service continues to serve traffic without interruption. The developer checks the CodeDeploy console and sees that the deployment is stuck in the 'InProgress' state with a status of 'Green fleet is not healthy.' What should the developer do to restore the deployment to a healthy state?

Accepted Answer

Stop the deployment in CodeDeploy and re-point the ALB listener to the blue target group.. Option B is correct because stopping the deployment and rerouting traffic to the blue target group ensures the blue service continues to serve traffic. Option A is wrong because manually updating the blue service does not address the stuck deployment. Option C is wrong because updating the green service may not fix the deployment. Option D is wrong because rolling back may not be available if the deployment is stuck.

Answer

Update the ECS task definition for the green service to a working version and wait for the deployment to complete.

Answer

Manually update the ECS service for the blue environment to increase the desired count.

Answer

Roll back the deployment to the previous version using the CodeDeploy console.

Question 12

A company is using AWS CodeDeploy to deploy an application to an Auto Scaling group. The deployment group has a deployment configuration of CodeDeployDefault.AllAtOnce. During a deployment, some instances fail the deployment. Which THREE actions should the developer take to improve the deployment health?

Accepted Answer

Change the deployment configuration to CodeDeployDefault.OneAtATime.. Option A (use CodeDeployDefault.OneAtATime) is correct because it reduces risk by deploying to one instance at a time. Option B (add a health check) is correct to catch issues early. Option D (use lifecycle hooks) is correct to run tests before instances are marked healthy. Option C is wrong because it does not help with deployment failures. Option E is wrong because it does not affect deployment health.

Answer

Increase the minimum number of healthy instances in the Auto Scaling group.

Answer

Use a larger instance type to handle the deployment load.

Question 13

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?

Accepted Answer

The RDS instance has reached its maximum number of concurrent connections because the application instances are not using connection pooling.. Option C is correct because when using a hardcoded connection string, each instance tries to connect using the same credentials, but RDS has a limit on the number of concurrent connections. As instances scale up, they may exceed the limit, causing intermittent timeouts. Option A is wrong because the security group is likely correct. Option B is wrong because RDS Multi-AZ is for failover, not connection limits. Option D is wrong because the errors are database-related, not application logic.

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 14

A DevOps engineer is implementing a blue/green deployment for a microservice running on Amazon ECS with Fargate. The service is fronted by an Application Load Balancer. During deployment, the new task set fails health checks, but the deployment does not automatically roll back. What is the MOST likely reason?

Accepted Answer

The ECS service deployment controller is set to 'ECS' instead of 'CODE_DEPLOY'.. Option A is correct. For blue/green deployments on ECS, you must specify a deployment controller type of 'CODE_DEPLOY' to use CodeDeploy and enable automatic rollback. If the controller is 'ECS' (the default), the deployment is managed by ECS and does not support automatic rollback on health check failures in blue/green mode. Option B is wrong because ECS does roll back if health checks fail when using ECS deployment controller with rolling update, but not for blue/green. Option C is wrong because CodeDeploy is not used if deployment controller is not CODE_DEPLOY. Option D is wrong because health check grace period delays health checks but does not prevent rollback if checks fail after grace period.

Answer

The CodeDeploy application and deployment group are not configured for automatic rollback.

Answer

The health check grace period is set too high.

Answer

The ECS service is configured with a 'minimum healthy percent' of 100 percent.

Question 15

A developer deploys a new version of an AWS Lambda function using the AWS CLI. The deployment fails with a 'ResourceConflictException' error. What is the most likely cause?

Accepted Answer

Another deployment is currently in progress for the same Lambda function.. The error occurs when trying to update a Lambda function's code while a deployment is in progress or when the function's reserved concurrency is being modified. Option B is correct because publishing a new version during an active deployment causes a conflict. Options A, C, and D are incorrect because missing IAM roles, incorrect handler names, or exceeding memory limits cause different errors.

Answer

The function's handler name is incorrect in the deployment package.

Answer

The Lambda function's IAM role is missing necessary permissions.

Answer

The Lambda function's memory limit is set too low for the deployment package.

Question 16

A company is implementing a CI/CD pipeline for a containerized application using Amazon ECS and AWS CodePipeline. The team wants to ensure zero-downtime deployments. Which THREE strategies should the team implement? (Choose THREE.)

Accepted Answer

Use a blue/green deployment strategy with an Application Load Balancer.. Options A, B, and D are correct. Using a blue/green deployment with a load balancer, configuring health checks, and using ECS service auto scaling ensure zero-downtime. Option C is incorrect because stopping all tasks causes downtime. Option E is incorrect because a rolling update with a fixed batch size can cause downtime if not managed carefully, but it is not the best practice; the question asks for three correct strategies.

Answer

Use a rolling update with a fixed batch size of 100% of tasks.

Answer

Stop all existing tasks before starting new tasks.

Question 17

A developer wants to deploy a static website to AWS. The website consists of HTML, CSS, and JavaScript files. Which combination of services provides the most cost-effective and scalable solution?

Accepted Answer

Amazon S3 and Amazon CloudFront. Amazon S3 can host static websites, and CloudFront provides CDN for low latency and scalability. Option A is correct. Option B (EC2) is more expensive and requires management. Option C (Elastic Beanstalk) is overkill. Option D (Lightsail) is a VPS but not as scalable for static content.

Answer

Amazon Lightsail

Answer

Amazon EC2 and Application Load Balancer

Answer

AWS Elastic Beanstalk

Question 18

A company uses AWS Elastic Beanstalk to deploy a web application. The development team wants to deploy a new version of the application to a separate environment for testing before switching production traffic. Which deployment strategy should be used?

Accepted Answer

Blue/green deployment.. Option D is correct because blue/green deployment creates a separate environment (green) for testing and then swaps URLs to switch traffic. Option A is wrong because all-at-once updates the current environment. Option B is wrong because rolling updates update instances in batches in the same environment. Option C is wrong because immutable updates create a new Auto Scaling group in the same environment.

Answer

Immutable deployment.

Answer

All at once deployment.

Answer

Rolling deployment.

Question 19

A developer needs to deploy a serverless application using AWS CloudFormation. The application includes an AWS Lambda function, an Amazon API Gateway REST API, and an Amazon DynamoDB table. The developer wants to create a stack that can be updated without downtime. Which CloudFormation feature should be used?

Accepted Answer

Change Sets. Option A is correct because Change Sets allow you to preview how changes will affect running resources before applying them, enabling you to plan for zero downtime. Option B is wrong because Nested Stacks are for modularity, not specifically for zero-downtime updates. Option C is wrong because StackSets are for multi-account/region deployments. Option D is wrong because Drift Detection identifies changes but does not prevent downtime.

Answer

Drift detection

Answer

StackSets

Answer

Nested stacks

Question 20

A developer is deploying an application using AWS Elastic Beanstalk. The developer wants to ensure that the application is highly available and can recover from an AZ failure. Which TWO configurations should be applied? (Choose TWO.)

Accepted Answer

Configure the environment to use multiple Availability Zones.. Options A and D are correct. A: Deploying to multiple AZs ensures that if one AZ fails, the application remains available. D: A load balancer distributes traffic across instances in multiple AZs. Option B is wrong because a single instance is not highly available. Option C is wrong because a larger instance type does not provide AZ redundancy. Option E is wrong because an RDS Multi-AZ database is for database availability, not application.

Answer

Select a larger EC2 instance type.

Answer

Enable Multi-AZ for the application's Amazon RDS database.

Answer

Use a single EC2 instance for simplicity.