How would you automate deployment and monitoring for a high-traffic Lambda app

How would you automate deployment and monitoring for a high-traffic Lambda app?
In event-driven, high-traffic serverless applications, the management of deployments and monitoring will be important. For this question, the strategies and tools of how to set up CI/CD pipelines for AWS Lambda will include how one could automate deployments and monitor performance metrics as well as track errors. Sample pipeline configurations, code snippets, and integration tips with AWS tools such as CodePipeline or CloudWatch as well as third-party services can help to present best practice scenarios keeping the application reliable and scalable.