Docker and Container Essentials

Containers are one of the most transformational technologies that we have seen in years. Technology companies, corporations, and end users have all adopted them to handle everyday workloads. Increasingly, commercial off-the-shelf (COTS) applications are transforming from traditional installations into fully containerized deployments. With such a large technology shift, it is essential for anyone in the information technology realm to learn about containers.

In this chapter, we will introduce the problems that containers address. After an introduction to why containers are important, we will introduce the runtime that launched the modern container frenzy, Docker, and explain its relationship to Kubernetes. We'll also cover how Kubernetes' recent deprecation of support for Docker as a runtime impacts the use of Docker and why you should still be familiar with how to use it. By the end of this chapter, you will understand how to install Docker and how to use the most common Docker CLI commands.

In this chapter, we will cover the following topics:

• Understanding the need for containerization
• Kubernetes deprecating Docker
• Understanding Docker
• Installing Docker
• Using the Docker CLI

Before we begin, you may have read that Kubernetes will be deprecating Docker as a compatible runtime in an upcoming release. This change will affect many businesses that work with containerization and Kubernetes. We will dig into it in the Understanding why Kubernetes is depreciating Docker section but rest assured that Docker is still the best way to introduce you to containers and the advantages that they deliver. It will still be used on many systems that run containers locally, rather than with an orchestration platform like Kubernetes.