Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications. By taking advantage of Docker's methodologies for shipping, testing, and deploying code, you can significantly reduce the delay between writing code and running it in production.
Installation of Docker is a reasonably simple process, prerequisites:
On your Raspberry Pi or over SSH, open Terminal:
$ sudo apt update && sudo apt upgrade -y - Updates system
$ sudo apt install docker.io -y - Installs Docker
Now Docker is installed, test it by:
$ sudo docker run hello-world
This should output a message and end.