Amazon Elastic Container Service (Amazon ECS) now supports running Windows Server 2019 containers. Amazon ECS provides an ECS-Optimized Windows Server Amazon Machine Image (AMI), which is based on the EC2 Windows Server 2019 AMI and includes Docker 18.09 and the ECS Agent 1.27. 

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/06/amazon-ecs-support-windows-server-2019-containers-generally-available/