Docker is a software platform that allows you to build, test, and deploy applications quickly.

Docker is highly reliable

Docker is highly scalable

Docker package software is standardized into units called containers

Containers allow you to easily package an application code, configurations, and dependencies into easy-to-use building blocks that deliver environmental consistency operational efficiency, developer productivity, and version control.

You can create Amazon ECS clusters within a new or existing VPC. After a cluster is up and running, you can define task definitions and services that specify which Docker container images to run across your clusters. Container images are stored in and pulled from container registries, which may exist within or outside of your AWS infrastructure.

The following diagram shows the architecture of an Amazon ECS environment using the Fargate launch type:

Docker is Open Source software. It provides the automation of

Linux application deployment in a software container.

We can do operating system level virtualization on Linux with

Docker.

Docker can package software in a complete file system that contains

software code, runtime environment, system tools, & libraries that

are required to install and run the software on a server.

https://www.docker.com/