Introduction to Docker

The first thing we will do in this chapter will be to explain the reasoning behind Docker and its architecture. We will cover Docker concepts such as images, layers, and containers. Next, we will install Docker and learn how to pull a sample, basic Java application image from the remote registry and run it on the local machine.

Docker was created as the internal tool in the platform as a service company, dotCloud. In March 2013, it was released to the public as open source. Its source code is freely available to everyone on GitHub at: https://github.com/docker/docker. Not only do the core Docker Inc. team work on the development of Docker, there are also a lot of big names sponsoring their time and effort to enhance and contribute to Docker such as Google, Microsoft, IBM, Red Hat, Cisco systems, and many others. Kubernetes is a tool developed by Google for deploying containers across clusters of computers based on best practices learned by them on Borg (Google's homemade container system). It compliments Docker when it comes to orchestration, automating deployment, managing, and scaling containers; it manages workloads for Docker nodes by keeping container deployments balanced across a cluster. Kubernetes also provides ways for containers to communicate with each other, without the need for opening network ports. Kubernetes is also an open source project, living on the GitHub at https://github.com/kubernetes/kubernetes. Everyone can contribute. Let's begin our journey with Docker first. The following will be covered in:

• We will start with the basic idea behind this wonderful tool and show the benefits gained from using it, in comparison to traditional virtualization
• We will install Docker on three major platforms: macOS, Linux, and Windows