[Reference: AWS documentation on Blue/Green Deployment., Step 2: Use an Application Load Balancer and Auto Scaling GroupThe 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 ConfigurationThe 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 HooksBefore 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 DeploymentAfter 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., , ]