Running a single container is easy. But when you need to run hundreds of containers across multiple servers, restart them when they die, and scale them according to traffic, you're faced with an entirely different problem. This "orchestrating multiple containers" is container orchestration, and Amazon ECS is AWS's answer. Fargate takes a step further — "don't even manage the servers that run those containers" — offering a serverless container model.
In DVA-C02, ECS/Fargate/ECR are central to the Deployment domain