Amazon EC2 Container Service (ECS) allows users to easily run and manage containerized applications at scale. It supports running containers on a cluster of EC2 instances, provides scheduling and health monitoring, and integrates with other AWS services. The Amazon EC2 Container Registry (ECR) is a fully managed Docker container registry that allows users to store and deploy container images. Common patterns for ECS include using it to run services/microservices and batch jobs by sharing resource pools across containers.