AWS Certified DevOps Engineer – Professional (DOP-C02) — Question 217

A company is using AWS CodeDeploy to automate software deployment. The deployment must meet these requirements:

• A number of instances must be available to serve traffic during the deployment. Traffic must be balanced across those instances, and the instances must automatically heal in the event of failure. • A new fleet of instances must be launched for deploying a new revision automatically, with no manual provisioning.
• Traffic must be rerouted to the new environment to half of the new instances at a time. The deployment should succeed if traffic is rerouted to at least half of the instances: otherwise, it should fail.
• Before routing traffic to the new fleet of instances, the temporary files generated during the deployment process must be deleted.
• At the end of a successful deployment, the original instances in the deployment group must be deleted immediately to reduce costs.

How can a DevOps engineer meet these requirements?

Answer options

• A. Use an Application Load Balancer and an in-place deployment. Associate the Auto Scaling group with the deployment group. Use the Automatically copy Auto Scaling group option, and use CodeDeployDefault.OneAtAtime as the deployment configuration. Instruct AWS CodeDeploy to terminate the original instances in the deployment group, and use the AllowTraffic hook within appspec.yml to delete the temporary files.
• B. Use an Application Load Balancer and a blue/green deployment. Associate the Auto Scaling group and Application Load Balancer target group with the deployment group. Use the Automatically copy Auto Scaling group option, create a custom deployment configuration with minimum healthy hosts defined as 50%, and assign the configuration to the deployment group. Instruct AWS CodeDeploy to terminate the original instances in the deployment group, and use the BeforeBlockTraffic hook within appspec.yml to delete the temporary files.
• C. Use an Application Load Balancer and a blue/green deployment. Associate the Auto Scaling group and the Application Load Balancer target group with the deployment group. Use the Automatically copy Auto Scaling group option, and use CodeDeployDefault.HalfAtAtime as the deployment configuration. Instruct AWS CodeDeploy to terminate the original instances in the deployment group, and use the BeforeAllowTraffic hook within appspec.yml to delete the temporary files.
• D. Use an Application Load Balancer and an in-place deployment. Associate the Auto Scaling group and Application Load Balancer target group with the deployment group. Use the Automatically copy Auto Scaling group option, and use CodeDeployDefault.AllatOnce as a deployment configuration. Instruct AWS CodeDeploy to terminate the original instances in the deployment group, and use the BlockTraffic hook within appspec.yml to delete the temporary files.

Correct answer: C

Explanation

Option C is correct because it uses a blue/green deployment strategy with the Application Load Balancer, which meets the requirement for traffic rerouting to half of the new instances at a time. The BeforeAllowTraffic hook is also appropriate as it ensures temporary files are deleted before traffic is sent to the new instances. Options A and D use in-place deployments, which do not satisfy the requirement for launching a new fleet of instances, while B does not utilize the correct deployment configuration required for the 50% healthy hosts criterion.