DOP-C02 Practice Test 2 — 25 Questions

Question 1

Refer to the exhibit. The deployment succeeded but the application fails. What is the MOST likely cause?

Accepted Answer

The new task definition has a misconfigured database connection string or security group.. The most common cause of a deployment succeeding but the application failing is a misconfiguration in the new task definition, such as an incorrect database connection string or a security group that does not allow traffic to the database. CodePipeline can successfully deploy the new task definition to ECS, but if the application cannot connect to its backend services due to these configuration errors, the application will fail at runtime. This aligns with the scenario where the deployment pipeline reports success but the application itself is non-functional.

Answer

The CodePipeline deployment action uses the wrong cluster.

Answer

The ECS service is not registered with a target group.

Answer

The database is not available in the same Availability Zone.

Question 2

A company runs a critical application on Amazon ECS with Fargate. They use blue/green deployments via AWS CodeDeploy. During a recent deployment, the new task set failed health checks and CodeDeploy automatically rolled back. However, the old task set also became unhealthy shortly after rollback. What could explain this?

Accepted Answer

The new application version changed the database schema, which broke the old version after rollback.. A backward-incompatible database schema change (e.g., a column removal or renaming) applied by the new application version can corrupt or invalidate the data that the old version relies on. When CodeDeploy rolls back to the old task set, the old application cannot function correctly with the altered schema, causing it to fail health checks. This is a classic rollback failure scenario where the deployment changes shared state (the database) that persists beyond the task set lifecycle.

Answer

The CloudWatch alarm that triggered the rollback also stopped the old task set.

Answer

CodeDeploy did not drain connections from the Application Load Balancer before terminating the old task set.

Answer

The ECS service auto-scaling policy reduced the desired count of the old task set during the deployment.

Question 3

A DevOps engineer is designing a CI/CD pipeline for a microservices application running on Amazon ECS with Fargate. The team wants to use a blue/green deployment strategy to minimize downtime. Which combination of AWS services and configurations should be used to implement this?

Accepted Answer

Use CodeDeploy with an ECS compute platform and an Application Load Balancer. CodeDeploy with an ECS compute platform natively supports blue/green deployments for ECS services by orchestrating traffic shifting between two target groups behind an Application Load Balancer. This approach minimizes downtime by gradually routing traffic from the 'blue' (current) task set to the 'green' (new) task set, with built-in rollback capabilities and lifecycle hooks for validation.

Answer

Use Amazon ECS service with a rolling update deployment controller

Answer

Create two separate ECS services and use Route 53 weighted routing to shift traffic

Answer

Use AWS CloudFormation with a custom resource to swap target group weights

Question 4

A company uses AWS CodeDeploy to deploy applications to an Auto Scaling group. The deployment fails because the new version of the application crashes the instances. The DevOps engineer needs the Auto Scaling group to automatically replace the unhealthy instances with the previous working version. Which deployment configuration should the engineer use?

Accepted Answer

Blue/Green deployment with a load balancer to switch traffic only after health checks pass.. A blue/green deployment with a load balancer health check ensures that the new (green) instances are validated before any traffic is routed to them. If the new version crashes, the health checks fail, the load balancer keeps traffic on the old (blue) instances, and the Auto Scaling group can automatically terminate the unhealthy green instances and replace them with the previous working version by reverting to the original launch configuration or template.

Answer

In-place deployment with a deployment group that has a failure threshold of 0.

Answer

Canary deployment that shifts 10% of traffic to the new version, then 100% after 10 minutes.

Answer

Linear deployment that shifts 10% of traffic every 10 minutes.

Question 5

A developer wants to provision AWS resources using AWS Cloud Development Kit (CDK) and ensure that the infrastructure can be version-controlled and reviewed. Which practice should they follow?

Accepted Answer

Write the CDK app in TypeScript, store it in a Git repository, and use CDK pipelines for deployment.. It follows the recommended practice of treating CDK application code as infrastructure source code, storing it in a version control system (Git), and using CDK Pipelines (a high-level construct that automatically synthesizes and deploys CloudFormation templates) to ensure repeatable, reviewed deployments. This approach enables infrastructure-as-code best practices: version history, peer review via pull requests, and automated deployment pipelines.

Answer

Write the CDK app and deploy directly without synthesis to avoid extra steps.

Answer

Write the CDK app to generate Terraform configurations and store them in Git.

Answer

Write raw CloudFormation templates instead of CDK to simplify version control.

Question 6

A company runs a critical application on Amazon ECS with the Fargate launch type. The application is deployed across three Availability Zones. Each service has its own Application Load Balancer. The company wants to implement a blue/green deployment strategy to reduce risk. They currently use AWS CodeDeploy for ECS deployments. During a recent deployment, the company noticed that the new version (green) was not receiving any traffic even after passing all health checks. The CodeDeploy configuration uses a 'Linear10PercentEvery3Minutes' traffic shifting configuration. What is the most likely reason that the green tasks are not receiving traffic?

Accepted Answer

The green target group's health check is misconfigured, causing CodeDeploy to consider the green tasks unhealthy and not route traffic.. The green target group's health check is misconfigured, causing CodeDeploy to consider the green tasks unhealthy. With a 'Linear10PercentEvery3Minutes' traffic shifting configuration, CodeDeploy gradually shifts traffic in 10% increments every 3 minutes, but only if the green target group passes health checks. If the health check fails, CodeDeploy stops traffic shifting, leaving the green tasks with zero traffic despite the tasks themselves being healthy.

Answer

The CodeDeploy deployment group is not associated with the correct ECS service.

Answer

The blue target group is still set as the production target group in the load balancer listener.

Answer

The green tasks are in a different VPC than the load balancer.

Question 7

An organization uses AWS CodePipeline to orchestrate deployments to multiple environments (dev, test, prod). Each environment uses a different AWS account. The pipeline uses cross-account actions with IAM roles. Recently, the pipeline failed at the deploy stage for the prod account with the error 'Access Denied' when assuming the cross-account role. The role ARN is correct and the trust policy allows the pipeline's service role. What is the MOST likely cause?

Accepted Answer

The pipeline's service role lacks the `sts:AssumeRole` permission for the cross-account role.. The pipeline's service role must have an `sts:AssumeRole` permission on the cross-account role to perform the role assumption. Even if the trust policy on the cross-account role allows the pipeline's service role, the pipeline's service role itself needs an IAM policy granting `sts:AssumeRole` for the cross-account role ARN. Without this permission, the `AssumeRole` API call fails with 'Access Denied', which is the exact error described.

Answer

The EC2 instances in the prod account do not have an appropriate instance profile.

Answer

The cross-account role's permissions boundary denies the deploy action.

Answer

The pipeline's service role does not have permission to perform the deploy action in the prod account.

Question 8

A DevOps engineer receives an alarm that an EC2 instance's CPU utilization has exceeded 90% for 5 minutes. The engineer needs to automatically recover the instance. Which AWS service should be used to configure automatic recovery?

Accepted Answer

Amazon CloudWatch Alarms. Amazon CloudWatch Alarms can be configured to trigger an EC2 instance recovery action when a metric like CPU utilization exceeds a threshold (e.g., 90% for 5 minutes). The alarm sends a signal to the EC2 service, which automatically recovers the instance by stopping it and starting it on a new underlying host, preserving the instance ID, private IP, and Elastic IP. This is the native, built-in mechanism for automatic instance recovery without requiring additional compute or orchestration services.

Answer

AWS Lambda

Answer

AWS Systems Manager Automation

Answer

EC2 Auto Scaling

Question 9

A company has a multi-account AWS environment with separate accounts for development, staging, and production. They want to implement a CI/CD pipeline that deploys to each account sequentially after manual approvals. Which setup allows cross-account deployment with CodePipeline?

Accepted Answer

Create an IAM role in the target account with permissions for the pipeline service role to assume, and use that role in the deployment action.. CodePipeline supports cross-account deployments by having the pipeline service role in the source account assume an IAM role in the target account. This role must have a trust policy allowing the pipeline service role to assume it, and the deployment action (e.g., CloudFormation, CodeDeploy) references that target account role. This enables sequential deployment to development, staging, and production accounts with manual approval gates between stages.

Answer

Create separate pipelines in each account and trigger them via SNS from a master pipeline.

Answer

Use CodePipeline with cross-account actions by specifying the target account ID and region.

Answer

Use a single pipeline in the management account with different stages for each account.

Question 10

A development team uses AWS CodeCommit for source control. They want to enforce that all commits include a JIRA issue key in the commit message. What is the MOST efficient way to achieve this?

Accepted Answer

Create a CodeCommit trigger that invokes an AWS Lambda function on every push to validate commit messages.. CodeCommit triggers can invoke an AWS Lambda function on every push event, allowing real-time validation of commit messages against a required pattern (e.g., JIRA issue key). This serverless approach enforces the policy centrally without relying on client-side configurations, making it the most efficient and reliable method for a team using AWS CodeCommit.

Answer

Use Amazon CloudWatch Events to detect new commits and invoke a Lambda function to validate the commit message.

Answer

Implement a pre-commit hook in each developer's local repository.

Answer

Configure a branch policy on the repository that requires commit message format.

Question 11

A company is deploying a critical application on Amazon EC2 instances behind an Application Load Balancer (ALB) across multiple Availability Zones. The application must be resilient to the failure of an entire Availability Zone. Which design should the company implement?

Accepted Answer

Launch EC2 instances in at least two Availability Zones and place them behind an Application Load Balancer with cross-zone load balancing enabled.. Deploying EC2 instances across at least two Availability Zones (AZs) behind an Application Load Balancer (ALB) with cross-zone load balancing enabled ensures that if an entire AZ fails, the ALB can route traffic to healthy instances in the remaining AZs. Cross-zone load balancing allows the ALB to distribute incoming requests evenly across all registered instances in all enabled AZs, which improves fault tolerance and resource utilization. This design meets the requirement for resilience to an AZ failure by eliminating a single point of failure at the AZ level.

Answer

Use one EC2 instance in a single Availability Zone behind a Network Load Balancer.

Answer

Launch EC2 instances in one Availability Zone and use an Application Load Balancer to distribute traffic.

Answer

Deploy EC2 instances in two Availability Zones but use a single Application Load Balancer in one AZ.

Question 12

A company runs a stateless web application on Amazon ECS with Fargate launch type. The application experiences intermittent traffic spikes. The company wants to ensure that the application can scale automatically and remain resilient to underlying infrastructure failures. Which combination of actions should the DevOps engineer take?

Accepted Answer

Configure an Application Auto Scaling target tracking policy based on memory utilization and enable Amazon ECS service auto-recovery.. It combines Application Auto Scaling target tracking based on memory utilization, which is a relevant metric for a stateless web application to handle traffic spikes, with Amazon ECS service auto-recovery, which automatically replaces unhealthy tasks to ensure resilience against underlying infrastructure failures. This approach provides both automatic scaling and fault tolerance without manual intervention.

Answer

Configure a scheduled scaling policy for the Amazon ECS service to add tasks during known peak hours.

Answer

Launch tasks in a single Availability Zone and use an Application Auto Scaling target tracking policy based on CPU utilization.

Answer

Configure a step scaling policy for the Amazon ECS service and increase the task memory size.

Question 13

A development team is using AWS CodeCommit to store source code and AWS CodePipeline to automate builds and deployments. The team wants to ensure that builds and tests are triggered only when code is pushed to specific branches, and that manual approval is required before deploying to production. Which CodePipeline configuration should the team implement?

Accepted Answer

Configure the source action with a branch filter for main, and add a manual approval step before the production deployment stage.. CodePipeline source actions support branch filters that restrict which Git branches trigger the pipeline. By filtering on 'main', only pushes to that branch initiate the pipeline. Adding a manual approval step before the production deployment stage ensures that no code reaches production without explicit human sign-off, meeting both requirements precisely.

Answer

Configure the source action to trigger on all branches and add a manual approval step before the build stage.

Answer

Configure the source action with a branch filter for main, and add a manual approval step before the build stage.

Answer

Use a branch filter on the build action to run only for the main branch, and add a manual approval step before the deploy stage.

Question 14

A DevOps team uses AWS CodePipeline with a multi-branch strategy. The pipeline should deploy to production only from the 'main' branch, but run unit tests for all branches. How should the team configure the pipeline?

Accepted Answer

Configure the pipeline source stage to trigger on all branches, use branch-specific logic in the test stage, and add a manual approval step for production deployment only when the branch is 'main'.. AWS CodePipeline supports branch filtering in the source stage to trigger on all branches, and you can use a condition in the deploy stage (e.g., via a Lambda function or a manual approval step) to restrict production deployment to the 'main' branch only. This approach avoids duplicating pipelines while ensuring unit tests run for every branch, meeting the multi-branch strategy requirement efficiently.

Answer

Use an AWS Lambda function to check the branch name and invoke different CodePipeline executions for testing and deployment.

Answer

Create one pipeline with two source stages: one for 'main' and one for all other branches, each with its own test and deploy actions.

Answer

Create a separate pipeline for each branch, each with identical test and deploy stages.

Question 15

A company is implementing a disaster recovery strategy for its Amazon Aurora MySQL database. The primary database is in us-west-2. The company requires an RPO of less than 1 minute and an RTO of less than 5 minutes. Which solution meets these requirements?

Accepted Answer

Use Amazon Aurora Global Database with a secondary Region cluster.. Amazon Aurora Global Database is designed for low-latency cross-Region replication with a typical RPO of 1 second and RTO of 1 minute or less, meeting the <1 minute RPO and <5 minute RTO requirements. It uses a dedicated storage-level replication channel that keeps the secondary cluster fully synchronized without impacting primary performance, and failover involves promoting the secondary cluster to primary in under a minute.

Answer

Create a cross-Region read replica in the secondary Region and promote it during failover.

Answer

Use automated backups and restore to a new DB instance in the secondary Region.

Answer

Take manual snapshots of the DB instance and copy them to the secondary Region every hour.

Question 16

A company uses Amazon CloudWatch Logs to store application logs. The DevOps team wants to search across multiple log groups for a specific error pattern. Which TWO options can be used to achieve this? (Choose TWO.)

Accepted Answer

Use CloudWatch Logs Insights to run queries across multiple log groups.. CloudWatch Logs Insights is purpose-built for querying log data across multiple log groups. It uses a query language to search, filter, and aggregate log events, making it ideal for identifying error patterns across different sources. This option is correct because it directly supports cross-log-group queries without additional data movement or infrastructure.

Answer

Install the CloudWatch Logs agent on an EC2 instance and tail the logs.

Answer

Create a Lambda function that reads logs from each log group and searches for the pattern.

Answer

Use Amazon Kinesis Data Analytics to process the log streams.

Question 17

A company runs a critical application on Amazon EC2 instances behind an Application Load Balancer. The application is deployed using AWS CodeDeploy with an in-place deployment configuration. During a recent deployment, the deployment failed because the new application version caused a health check failure, and CodeDeploy did not automatically roll back. What should the engineer do to ensure automatic rollback on health check failure?

Accepted Answer

Enable automatic rollback in the CodeDeploy deployment group and set up a CloudWatch alarm for the ALB health check. CodeDeploy can automatically roll back a deployment when a CloudWatch alarm, such as one monitoring ALB health check failures, enters the ALARM state. By enabling automatic rollback in the deployment group and associating the CloudWatch alarm, the deployment will revert to the previous version as soon as the health check fails, without manual intervention.

Answer

Set up an EC2 instance lifecycle hook to trigger a rollback script when the instance enters a pending state

Answer

Configure an Amazon SQS queue to monitor health checks and invoke a rollback Lambda function

Answer

Modify the Auto Scaling group to replace unhealthy instances automatically

Question 18

Refer to the exhibit. A DevOps engineer ran the above AWS CLI command after a CloudFormation stack update. What does the status 'ROLLBACK_COMPLETE' indicate?

Accepted Answer

The stack update failed and CloudFormation reverted to the previous stack.. The 'ROLLBACK_COMPLETE' status indicates that the CloudFormation stack update operation failed, and CloudFormation automatically reverted the stack to its previous stable state. This is a built-in safety mechanism: if any resource fails to update, CloudFormation triggers a rollback to undo all changes made during the update, ensuring the stack returns to its last known good configuration.

Answer

The stack update is in progress.

Answer

The stack was deleted successfully.

Answer

The stack was created successfully.

Question 19

A company uses AWS CodeBuild to compile and test code. The buildspec.yml file includes commands that require access to a private S3 bucket. The DevOps engineer wants to securely provide AWS credentials to the build project. What is the recommended approach?

Accepted Answer

Use a service role for CodeBuild with appropriate permissions. The recommended approach is to use a service role for CodeBuild with appropriate permissions. CodeBuild can assume an IAM role that grants the build project access to the private S3 bucket, eliminating the need to manage long-term credentials. This follows AWS best practices for secure credential management by using temporary, automatically rotated credentials via the AWS Security Token Service (STS).

Answer

Store the AWS access key ID and secret access key in the buildspec.yml file

Answer

Use an EC2 instance profile attached to the build environment

Answer

Pass the credentials as environment variables in the build project configuration

Question 20

A company uses AWS CloudFormation to deploy infrastructure. They have a template that creates an Amazon EC2 instance and an Elastic IP address. The template uses the AWS::EC2::EIP resource. The team notices that when they delete the stack, the Elastic IP address is not released, leading to charges. They want to ensure that the Elastic IP is automatically released when the stack is deleted. What should they do?

Accepted Answer

Set the DeletionPolicy attribute to 'Delete' on the EIP resource. The default DeletionPolicy for AWS::EC2::EIP is 'Retain', meaning the Elastic IP address is preserved after stack deletion, leading to charges. To ensure it is automatically released, you must explicitly set the DeletionPolicy attribute to 'Delete' on the EIP resource. This overrides the default and causes the Elastic IP to be deleted upon stack deletion. Option A (Retain) would keep the EIP, which is the default and would still incur charges. Option B (custom resource) is unnecessary. Option D (DependsOn) does not control deletion behavior. Therefore, Option C is the correct solution.

Answer

Set the DeletionPolicy attribute to 'Retain' to keep the EIP

Answer

Create a custom resource to release the EIP before stack deletion

Answer

Add a DependsOn clause to ensure proper order of deletion