Which service runs Docker apps across a cluster of EC2 instances with orchestration support?

• A. AWS Lambda
• B. Amazon Elastic Container Registry (Amazon ECR)
• C. AWS Outposts
• D. Amazon Elastic Container Service (Amazon ECS)

Answer: (D)

Container orchestration across a cluster of EC2 instances is what Amazon Elastic Container Service is built for. ECS manages the deployment, scheduling, and lifecycle of Docker containers across a managed cluster, handling where each container runs, scaling services, performing rolling updates, and monitoring health. It can run containers on EC2 instances or use Fargate to run them without managing servers, all while integrating with load balancers, IAM, and CloudWatch.

The other options don’t fit this role: Lambda runs short-lived code in response to events and doesn’t orchestrate a cluster of containers; ECR is a container image registry that stores Docker images but doesn’t run them; Outposts brings AWS services to on-premises hardware and isn’t, by itself, a container orchestration service.