DVA-C02 Practice Exam 54 — 20 Questions

Question 1

A developer is deploying a serverless application using AWS SAM. The application consists of an API Gateway REST API and multiple AWS Lambda functions. The developer wants to deploy the application to a production environment with minimal downtime. Which deployment strategy should the developer use?

Accepted Answer

Use SAM's built-in canary deployment with traffic shifting.. Option A is correct because AWS SAM supports canary deployments, which allow traffic shifting gradually to new versions, minimizing downtime. Option B is wrong because rolling updates are not natively supported by SAM for Lambda. Option C is wrong because blue/green deployments require manual setup and are not built into SAM. Option D is wrong because replacing the stack causes downtime.

Answer

Create a blue/green deployment using AWS Elastic Beanstalk.

Answer

Delete the existing stack and deploy a new one.

Answer

Perform a rolling update by updating functions one by one.

Question 2

A company uses AWS CloudFormation to manage infrastructure. The development team wants to make a change to a stack that involves replacing a critical resource. The team wants to minimize downtime and ensure that the replacement is successful before removing the old resource. Which CloudFormation feature should the team use?

Accepted Answer

Use a CreationPolicy on the resource to ensure it is fully created before the old one is deleted.. Option D is correct because CloudFormation stack updates with replacement use the 'create before destroy' policy when the resource has a 'DeletionPolicy' of 'Retain' or when using a custom resource with a 'CreationPolicy'. However, the best way is to use a 'CreationPolicy' on the resource to ensure it is fully created before the old is destroyed. Option A is wrong because change sets are for preview, not ordering. Option B is wrong because it is not a CloudFormation feature. Option C is wrong because nested stacks do not control replacement order.

Answer

Use AWS CodeDeploy blue/green deployment.

Answer

Use a change set to review the changes before executing.

Answer

Use nested stacks to isolate the resource.

Question 3

A developer performed a CodeDeploy deployment to an Auto Scaling group. The deployment status is Failed with code HEALTH_CONSTRAINTS. Based on the exhibit, what is the most likely cause?

Accepted Answer

The minimum number of healthy instances required for the deployment was not met. The error 'HEALTH_CONSTRAINTS' means that too many instances failed health checks. The deployment overview shows 2 failed instances and 3 succeeded. The minimum healthy instances setting likely required more than 3 healthy instances. Option B is correct. Option A (incorrect application revision) would cause a different error. Option C (CodeDeploy agent) would show agent issues. Option D (permissions) would cause access denied errors.

Answer

The CodeDeploy agent on the instances is not running

Answer

The application revision contains invalid scripts

Answer

The IAM role for CodeDeploy does not have sufficient permissions

Question 4

A company is implementing a CI/CD pipeline using AWS CodeCommit, CodeBuild, and CodeDeploy. The developer wants to ensure that the pipeline automatically deploys to production only after a manual approval step. Which TWO actions should the developer take?

Accepted Answer

Add a manual approval action in the CodePipeline pipeline.. Option B and Option D are correct. Adding an approval action in CodePipeline pauses the pipeline until manual approval. CodePipeline natively supports manual approval actions. Option A is wrong because SNS is used for notifications, not approval. Option C is wrong because CodeDeploy does not have a built-in manual approval step; it can use lifecycle hooks but not manual approval. Option E is wrong because CloudWatch Events can trigger pipelines but not provide manual approval.

Answer

Create a CloudWatch Events rule to trigger a Lambda function that waits for approval.

Answer

Use a CodeDeploy lifecycle hook to pause the deployment.

Answer

Configure an SNS topic to send an email to the approver.

Question 5

A company deploys a microservices application using AWS CloudFormation. Each microservice is deployed as a separate stack. The developer wants to pass the output values (e.g., API endpoint URLs) from one stack to another. Which CloudFormation feature should be used?

Accepted Answer

Cross-stack references using Export and ImportValue. Option C is correct because cross-stack references using Fn::ImportValue and Export allow you to pass outputs from one stack to another. Option A is wrong because nested stacks are for hierarchical dependencies, not independent stacks. Option B is wrong because Outputs are not automatically available to other stacks. Option D is wrong because custom resources are for custom logic, not simple value passing.

Answer

Custom resources with Lambda

Answer

Stack outputs

Answer

Nested stacks

Question 6

A company uses AWS CodeDeploy to deploy a web application to an Auto Scaling group. The deployment fails during the 'Install' lifecycle event. The developer checks the logs and finds that the scripts in the 'appspec.yml' file are not being executed because the instances are not in a healthy state. What could be the reason for the instances being unhealthy?

Accepted Answer

The health check grace period on the Auto Scaling group is too short.. Option D is correct because if the health check grace period is too short, instances may be marked unhealthy before the deployment scripts complete. Option A is wrong because insufficient IAM permissions would cause a different error (e.g., access denied). Option B is wrong because incorrect ELB configuration would cause load balancer issues, not instance health. Option C is wrong because CodeDeploy agent version is unrelated to instance health checks.

Answer

The Elastic Load Balancer is not configured to route traffic to the Auto Scaling group.

Answer

The CodeDeploy agent on the instances is outdated.

Answer

The IAM instance profile does not have permissions to access the S3 bucket where the artifacts are stored.

Question 7

A developer is trying to update a CloudFormation stack that includes a Lambda function. The stack rolls back with the error shown. What is the most likely cause?

Accepted Answer

The Lambda function's execution role does not have a trust policy that allows Lambda to assume it.. Option A is correct because the error states that the role cannot be assumed by Lambda, meaning the trust policy of the IAM role does not include 'lambda.amazonaws.com' as a trusted entity. Option B is wrong because the error is about the role, not permissions. Option C is wrong because the error is not about S3. Option D is wrong because the function code is not the issue.

Answer

The Lambda function's execution role lacks permissions to write logs to CloudWatch.

Answer

The Lambda function's deployment package is not stored in Amazon S3.

Answer

The Lambda function's code is too large for the deployment.

Question 8

A company uses AWS CodePipeline to deploy a static website to Amazon S3. The pipeline has a build stage that compiles the website and a deploy stage that syncs the build output to an S3 bucket. After a recent change, the pipeline succeeds but the website does not show the updated content. What is the most likely cause?

Accepted Answer

Amazon CloudFront is caching the old content and needs an invalidation.. Option B is correct because S3 static websites often use CloudFront for caching; an invalidation is needed after updates. Option A is wrong because if the bucket policy blocked uploads, the deploy stage would fail. Option C is wrong because if the build output was empty, the deploy would still sync (maybe nothing changes). Option D is wrong because CodePipeline would have failed if the deploy action failed.

Answer

The build output is empty because the build failed silently.

Answer

The deploy action is configured to skip if the source content has not changed.

Answer

The S3 bucket policy does not allow public read access.

Question 9

Refer to the exhibit. A developer deploys this CloudFormation template. After deployment, the S3 bucket is created but the developer notices that the lifecycle rule does not appear in the bucket's management console. What is the most likely cause?

Accepted Answer

The lifecycle rule is missing the 'Prefix' property, causing it to be invalid.. Option B is correct because lifecycle rules require the prefix to be specified; if omitted, the rule applies to the entire bucket but may not show in the console due to a display issue. However, the rule should be active. Option A is wrong because VersioningConfiguration is correct. Option C is wrong because the rule does not require a prefix. Option D is wrong because bucket name is unique.

Answer

The lifecycle rule must have a 'Transitions' property.

Answer

The VersioningConfiguration is incorrectly specified.

Answer

The bucket name contains an account ID, which is not allowed.

Question 10

A company is using 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, too few healthy instances are available, or some instances in your deployment group are experiencing problems.' The application is deployed to a t2.micro instance with 1 GB of RAM. The deployment uses an in-place update with a deployment configuration that has a minimum of 1 healthy host. What is the most likely cause of the failure?

Accepted Answer

The application uses too much memory, causing the instance to become unhealthy during deployment.. Option B is correct because the t2.micro instance has limited memory, and the application may cause out-of-memory errors during deployment. Option A is wrong because CodeDeploy agent timeout is typically 30 minutes, but the error mentions 'too few healthy instances', not timeout. Option C is wrong because IAM role permissions would cause a different error. Option D is wrong because insufficient disk space is less likely given the instance type has 8 GB EBS.

Answer

The instance does not have enough disk space to download the application revision.

Answer

The CodeDeploy agent timed out because the deployment took longer than 30 minutes.

Answer

The IAM role for the CodeDeploy agent does not have sufficient permissions to deploy the application.

Question 11

A development team is using AWS Elastic Beanstalk to deploy a web application. The team wants to perform a blue/green deployment. Which THREE steps are required to complete the blue/green deployment?

Accepted Answer

Swap the CNAMEs of the two environments.. Options A, C, and D are correct. In a blue/green deployment with Elastic Beanstalk, you deploy the new version to a separate environment (A), then swap the CNAMEs (C), and finally terminate the old environment (D). Option B is wrong because you don't update the old environment; you create a new one. Option E is wrong because you swap CNAMEs, not update DNS records manually.

Answer

Update the existing environment with the new version.

Answer

Update the Route 53 DNS record to point to the new environment.

Question 12

A company is deploying a new web application on Amazon EC2 instances behind an Application Load Balancer. The application must be deployed with no downtime. The deployment uses AWS CodeDeploy with a Blue/Green deployment configuration. Which TWO actions should be taken to achieve zero-downtime deployment? (Choose TWO.)

Accepted Answer

Create a new Auto Scaling group with the new application version and register it with the ALB.. Options A and D are correct. A: If the new environment passes tests, traffic is shifted to it. D: Before shifting traffic, the new environment must be fully tested. Option B is wrong because terminating old instances immediately would cause downtime if the new environment fails. Option C is wrong because the new environment should be created first, not updated in-place. Option E is wrong because the load balancer is already in place; you should register the new instances with the existing ALB.

Answer

Create a new load balancer for the new environment.

Answer

Update the existing Auto Scaling group with the new application version.

Answer

Terminate the old EC2 instances immediately after deploying the new ones.

Question 13

A company uses AWS CodePipeline to automate deployments of a microservices application to Amazon ECS with Fargate. The pipeline has a deploy stage that uses Amazon ECS Blue/Green deployment. The deployment fails intermittently with a 'Task failed to start' error. The developer needs to troubleshoot the issue. Which THREE steps should the developer take? (Choose three.)

Accepted Answer

Check the Amazon ECS service events for the task failure reason.. Options A, C, and E are correct because checking ECS service events (A) gives direct error messages, validating the task definition (C) ensures container configuration is correct, and verifying the IAM role (E) addresses permission issues. Option B is wrong because CodeBuild logs are for build, not deploy. Option D is wrong because CloudFormation events are not relevant for ECS deployments.

Answer

Review the CodeBuild build logs for errors.

Answer

Check the CloudFormation stack events for the ECS service.

Question 14

A developer is deploying a static website to Amazon S3. The developer wants to enable versioning to easily roll back to a previous version if the new deployment has issues. After enabling versioning on the bucket, the developer uploads the new files. How can the developer roll back to the previous version?

Accepted Answer

Copy the previous version of the object to the same key, making it the current version.. Option B is correct because with versioning enabled, you can restore a previous version by copying it to the same key, making it the current version. Option A is wrong because deleting the current version does not restore the previous one. Option C is wrong because there is no 'Restore' action like in RDS. Option D is wrong because you cannot simply 'enable' a previous version; you must copy it.

Answer

Delete the current version of the object from the bucket.

Answer

Use the S3 console 'Restore' action on the bucket.

Answer

Enable 'Show versions' and then select the previous version to make it current.

Question 15

A developer is using AWS CodeDeploy to deploy an application to an EC2 instance. The deployment fails with the error 'The overall deployment failed because the deployment group did not have enough instances to successfully deploy.' What is the most likely cause?

Accepted Answer

The deployment group contains zero instances.. Option A is correct because the deployment group must have at least one instance. Option B is wrong because CodeDeploy agent issues cause instance-level failures. Option C is wrong because action failures cause different errors. Option D is wrong because revision errors cause different errors.

Answer

The revision has an incorrect file format.

Answer

The CodeDeploy agent on the instance is not running.

Answer

The appspec file contains an invalid lifecycle hook.

Question 16

A company uses AWS CodePipeline to deploy a web application. The deployment fails intermittently during the 'Deploy' stage. The pipeline includes a step that runs a shell script on an EC2 instance. The pipeline uses a CodeBuild project for the build stage. What is the MOST likely cause of the intermittent failure?

Accepted Answer

The EC2 instance used for deployment does not have the CodeDeploy agent installed.. Option B is correct because if the EC2 instance is terminated or replaced, the CodeDeploy agent may not be installed, causing intermittent failures. Option A is wrong because CodeBuild uses temporary instances. Option C is wrong because CodePipeline does not require a VPC. Option D is wrong because IAM roles are not updated automatically.

Answer

The CodeBuild project is using an outdated build image.

Answer

The pipeline is not configured to use a VPC.

Answer

The IAM role for CodePipeline does not have permissions to deploy.

Question 17

Refer to the exhibit. A developer is trying to deploy an EC2 instance using AWS CloudFormation. The stack creation fails with an 'AccessDenied' error when CloudFormation tries to create the EC2 instance. The developer has the IAM policy above. What is the MOST likely reason for the failure?

Accepted Answer

The IAM role specified in the CloudFormation template is not the same as the one in the PassRole resource.. Option D is correct because CloudFormation needs permission to pass the IAM role specified in the template. The policy only allows PassRole for a specific role, but CloudFormation may be passing a different role. Option A is wrong because DescribeImages is allowed. Option B is wrong because RunInstances is allowed. Option C is wrong because CloudFormation does not call TerminateInstances during creation.

Answer

The policy does not allow ec2:DescribeImages.

Answer

The policy does not allow ec2:RunInstances.

Answer

The policy does not allow ec2:TerminateInstances.

Question 18

The exhibit shows the output of the describe-stack-events command for a CloudFormation stack that failed to create. What is the most likely cause of the failure?

Accepted Answer

The Lambda function handler 'index.handler' does not exist in the deployment package.. Option A is correct because the stack event shows CREATE_FAILED for the Lambda function resource, which could be due to an incorrect handler name. Option B is wrong because the S3 bucket and key are provided. Option C is wrong because there is no indication of a permissions issue; the event does not show an error message. Option D is wrong because there is no indication of a missing S3 bucket.

Answer

The S3 bucket 'my-bucket' does not contain the object 'my-function.zip'.

Answer

The Lambda function code exceeds the maximum allowed size.

Answer

The IAM role associated with the Lambda function lacks necessary permissions.

Question 19

A developer is creating a deployment pipeline using AWS CodePipeline. The pipeline includes a source stage from Amazon S3, a build stage using AWS CodeBuild, and a deploy stage using AWS CloudFormation. The developer wants to ensure that the pipeline can automatically create the CloudFormation stack if it does not exist. Which action mode should the developer use in the CloudFormation deploy action?

Accepted Answer

CREATE_UPDATE. Option B is correct because the 'CREATE_UPDATE' action mode creates a new stack if it does not exist or updates it if it does. Option A is wrong because 'REPLACE_ON_FAILURE' only replaces a failed stack. Option C is wrong because 'CREATE_ONLY' only creates a stack, not update. Option D is wrong because 'UPDATE_ONLY' only updates an existing stack, fails if not exist.

Answer

UPDATE_ONLY

Answer

REPLACE_ON_FAILURE

Answer

CREATE_ONLY

Question 20

A company is using AWS CodeDeploy to deploy a web application to an Auto Scaling group of EC2 instances. The deployment fails with the error 'The overall deployment failed because too many individual instances failed deployment.' What is the most likely cause?

Accepted Answer

The number of instances that failed deployment exceeded the configured failure threshold.. Option C is correct because CodeDeploy has a failure threshold that, when exceeded, fails the entire deployment. Option A is wrong because insufficient capacity would cause a different error. Option B is wrong because IAM permissions would cause access denied errors. Option D is wrong because missing tags would cause a different error.

Answer

The application specification file (appspec) is missing required hooks.

Answer

The IAM role for CodeDeploy does not have sufficient permissions to call EC2 APIs.

Answer

The Auto Scaling group does not have enough instances to meet the minimum healthy count.