DOP-C02 Practice Test 3 — 10 Questions

Question 1

A DevOps engineer is reviewing the CodePipeline structure above. The pipeline fails during the Deploy stage with an error: 'The deployment group could not be found.' What is the most likely cause?

Accepted Answer

The pipeline is configured as a single-region pipeline, but the Deploy action is in a different region.. The error 'The deployment group could not be found' indicates that CodePipeline is attempting to invoke a CodeDeploy deployment in a region where the specified deployment group does not exist. If the pipeline is configured as a single-region pipeline (e.g., in us-east-1) but the Deploy action references a deployment group in a different region (e.g., us-west-2), CodePipeline will fail because it cannot resolve the deployment group across regions in a single-region pipeline configuration. Cross-region actions require explicit cross-region action configuration in the pipeline structure.

Answer

The source artifact is not accessible from us-west-2.

Answer

The CodeDeploy application does not exist in us-west-2.

Answer

The CodeBuild project is not configured to output artifacts.

Question 2

A development team uses AWS CodeCommit for source control and AWS CodePipeline for CI/CD. The pipeline has a source stage that pulls from a CodeCommit repository, a build stage using AWS CodeBuild, and a deploy stage that uses AWS CodeDeploy to deploy to an EC2 Auto Scaling group. The team notices that the pipeline frequently fails at the deploy stage with the error 'The deployment failed because the deployment group's deployment configuration specifies a minimum healthy host count of 1, but 0 healthy hosts are available.' What is the MOST likely cause of this issue?

Accepted Answer

The CodeDeploy agent is not installed or is not running on the EC2 instances.. The error message indicates that the CodeDeploy deployment is failing because zero healthy hosts are available in the deployment group. The most common cause is that the CodeDeploy agent is not installed or not running on the EC2 instances, preventing them from reporting their health status to the CodeDeploy service. Without a healthy agent, the instances cannot execute the deployment lifecycle hooks, and CodeDeploy considers them unhealthy, leading to the failure.

Answer

The IAM role for CodePipeline does not have sufficient permissions to access the CodeCommit repository.

Answer

The build artifacts are not being stored in an S3 bucket.

Answer

The EC2 instances are not registered with a Classic Load Balancer.

Question 3

A company runs a stateless web application on EC2 instances in an Auto Scaling group across three Availability Zones. The application uses an Application Load Balancer. The operations team needs to ensure that the application remains available if one AZ fails. Which solution is MOST resilient?

Accepted Answer

Configure the Auto Scaling group to launch instances in three Availability Zones with a desired capacity of 3.. Distributing instances across three Availability Zones (AZs) with a desired capacity of 3 ensures that even if one AZ fails, the remaining two AZs still have at least 2 instances running, maintaining service capacity. The Application Load Balancer (ALB) automatically routes traffic away from the failed AZ, and the Auto Scaling group will replace lost instances in the healthy AZs, providing the highest resilience against a single-AZ failure.

Answer

Configure the Auto Scaling group to launch instances in a single Availability Zone with a desired capacity of 6.

Answer

Configure the Auto Scaling group to launch instances in two Availability Zones with a desired capacity of 4.

Answer

Configure the Auto Scaling group to launch instances in two Availability Zones with a desired capacity of 6, all in one AZ.

Question 4

A company uses Amazon CloudWatch Logs to store application logs. A DevOps engineer needs to create a real-time dashboard that displays the count of ERROR-level log entries across all instances. Which approach is the MOST efficient and cost-effective?

Accepted Answer

Use CloudWatch Logs Insights to run a query that counts ERROR entries across all log groups and add the query to a CloudWatch dashboard. CloudWatch Logs Insights allows you to run a query across all log groups in real time using a single query, and you can add that query directly to a CloudWatch dashboard. This approach is both efficient (no need to create per-log-group metric filters) and cost-effective (you pay only for the data scanned by the query, not for ongoing metric filter evaluation).

Answer

Create a CloudWatch Logs metric filter for each log group to count ERROR entries, and then create a CloudWatch dashboard

Answer

Export logs to Amazon S3 and use Amazon Athena to query and visualize in Amazon QuickSight

Answer

Create a Kinesis Data Firehose delivery stream to stream logs to Amazon OpenSearch Service and build a dashboard in OpenSearch Dashboards

Question 5

A company has a monolith application that takes over an hour to build. The DevOps team wants to implement continuous integration using AWS CodeBuild. The build environment requires a large amount of dependencies that are rarely updated. Which strategy will MINIMIZE build time and cost?

Accepted Answer

Create a custom Docker image that includes all dependencies and use it as the build environment.. By pre-baking all rarely-updated dependencies into a custom Docker image, the build environment is ready instantly without any download or installation steps. This eliminates the overhead of fetching dependencies at build time, which is the primary bottleneck for a monolith with a large dependency set, and minimizes both build duration and cost by reducing compute time.

Answer

Enable Amazon S3 cache for the CodeBuild project to reuse dependencies from previous builds.

Answer

Store the dependencies in an Amazon S3 bucket and download them at the start of each build.

Answer

Use a larger compute type for the CodeBuild project to speed up the build.

Question 6

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 7

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 8

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 9

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 10

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.