1. Create ECS cluster is creating the management of EC2 instances.
ECS cluster create and recreate EC2 instance if it's terminated automatically.
2. EC2 Ami Id*: THis is the amazon image for EC2 instance. AMI linux-2 is the latest with 30GB EBS volume for root image.
3. EBS storage (GiB)*: Extra EBS volume for docker data. It's mounted to EC2 instance at /dev/xdvcz
Amazon ECS-optimized Amazon Linux AMIs from version 2015.09.d and later launch with an 8-GiB volume for the operating system that is attached at /dev/xvda and mounted as the root of the file system. There is an additional 22-GiB volume that is attached at /dev/xvdcz that Docker uses for image and metadata storage