Docker runs as a background Windows service. This service manages every running container – it's called the Docker Engine. The engine exposes a REST API for consumers to work with containers and other Docker resources. The main consumer of this API is the Docker command-line tool (CLI), which is what I use for most of the code samples in this book.

The Docker REST API is public, and there are alternative management tools that are powered by the API, including web UIs like  Portainer (which is open source), and Docker Universal Control Plane (UCP) (which is a commercial product). The Docker CLI is very simple to use - you use commands like docker container run to run an application in a container and docker container rm to remove a container.

You can also configure the Docker API to be remotely accessible and configure your Docker CLI to connect to a remote service. This means you can manage a Docker host running in the cloud using Docker commands on your laptop. The setup to allow remote access can also include encryption, so your connection is secure – and in this chapter, I will show you an easy way to configure this.

Once you have Docker running, you'll start by running containers from images.