A Web Application with Multiple Services Runs on Amazon EC2

Multiple Choice

A web application with multiple services runs on Amazon EC2 instances behind an Application Load Balancer. The application stores data in an Amazon RDS Multi-AZ DB instance. The instance health check used by the load balancer returns PASS if at least one service is running on the instance. The company uses AWS CodePipeline with AWS CodeBuild and AWS CodeDeploy steps to deploy code to test and production environments. Recently, a new version was unable to connect to the database server in the test environment. One process was running, so the health checks reported healthy and the application was promoted to production, causing a production outage. The company wants to ensure that test builds are fully functional before a promotion to production. Which changes should a DevOps Engineer make to the test and deployment process? (Choose two.)

A) Add an automated functional test to the pipeline that ensures solid test cases are performed.
B) Add a manual approval action to the CodeDeploy deployment pipeline that requires a Testing Engineer to validate the testing environment.
C) Refactor the health check endpoint the Elastic Load Balancer is checking to better validate actual application functionality.
D) Refactor the health check endpoint the Elastic Load Balancer is checking to return a text-based status result and configure the load balancer to check for a valid response.
E) Add a dependency checking step to the existing testing framework to ensure compatibility.