This document discusses running containerized applications at scale on AWS. It begins by explaining why containers are used and the challenges of scaling container workloads, such as resource and state management, monitoring, service discovery, and deployment. It then provides an overview of Amazon ECS concepts like clusters, tasks, and services. The rest of the document discusses how to address the scaling challenges with services like Application Auto Scaling, service discovery options, monitoring with CloudWatch, logging with CloudWatch Logs, task scheduling and placement strategies, IAM roles, and demoing an application on ECS.