A company is using AWS CodeDeploy to automate software deployment. The deployment must meet these requirements: • A number of instances must be…

C Step 1: Use a Blue/Green Deployment Strategy A blue/green deployment strategy is necessary to meet the requirement of launching a new fleet of instances for each deployment and ensuring availability. In a blue/green deployment, the new version (green environment) is deployed to a separate set of instances, while the old version (blue environment) remains active. After testing the new version, traffic can be gradually shifted. Action: Use AWS CodeDeploy's blue/green deployment configuration. Why: Blue/green deployment minimizes downtime and ensures that traffic is shifted only to healthy instances. Reference: AWS documentation on Blue/Green Deployment. Step 2: Use an Application Load Balancer and Auto Scaling Group The Application Load Balancer (ALB) is essential to balance traffic across multiple instances, and Auto Scaling ensures the deployment scales automatically to meet demand. Action: Associate the Auto Scaling group and Application Load Balancer target group with the deployment group. Why: This configuration ensures that traffic is evenly distributed and that instances automatically scale based on traffic load. Reference: AWS documentation on Deploying with Auto Scaling and Load Balancing. Step 3: Use Custom Deployment Configuration The company requires that traffic be rerouted to at least half of the instances to succeed. AWS CodeDeploy allows you to configure custom deployment settings with specific thresholds for healthy hosts. Action: Create a custom deployment configuration where 50% of the instances must be healthy. Why: This ensures that the deployment continues only if at least 50% of the new instances are healthy. Reference: AWS documentation on Deployment Configurations. Step 4: Clean Temporary Files Using Hooks Before routing traffic to the new environment, the temporary files generated during the deployment must be deleted. This can be achieved using the BeforeAllowTraffic hook in the appspec.yml file. Action: Use the BeforeAllowTraffic lifecycle event hook to clean up temporary files before routing traffic to the new environment. Why: This ensures that the environment is clean before the new instances start serving traffic. Reference: AWS documentation on AppSpec File Hooks. Step 5: Terminate Original Instances After Deployment After a successful deployment, AWS CodeDeploy can automatically terminate the original instances (blue environment) to save costs. Action: Instruct AWS CodeDeploy to terminate the original instances after the new instances are healthy. Why: This helps in cost reduction by removing unused instances after the deployment. Reference: AWS documentation on Terminate Old Instances. This corresponds to Option 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.