Book Image

Docker Deep Dive

By : Nigel Poulton
Book Image

Docker Deep Dive

By: Nigel Poulton

Overview of this book

Most applications, even the funky cloud-native microservices ones, need high-performance, production-grade infrastructure to run on. Having impeccable knowledge of Docker will help you to thrive in the modern cloud-first world. With this book, you’ll gain the skills you need to work with Docker and its containers. The book begins with an introduction to containers and explains its functionality and application in the real world. You’ll then get an overview of VMware, Kubernetes, and Docker and learn to install Docker on Windows, Mac, and Linux. Once you’ve understood the Ops and Dev perspective of Docker, you’ll be able to see the big picture and understand what Docker exactly does. The book then turns its attention to the more technical aspects, guiding your through practical exercises covering Docker engine, Docker images, and Docker containers. You’ll learn techniques for containerizing an app, deploying apps with Docker Compose, and managing cloud-native applications with Swarm. You’ll also build Docker networks and Docker overlay networks and handle applications that write persistent data. Finally, you’ll deploy apps with Docker stacks and secure your Docker environment. By the end of this book, you’ll be well-versed in Docker and containers and have developed the skills to create, deploy, and run applications on the cloud.
Table of Contents (3 chapters)

6: Images

In this chapter we’ll dive deep into Docker images. The aim of the game is to give you a solid understanding of what Docker images are, how to perform basic operations, and how they work under-the-hood.

We’ll see how to build new images with our own applications inside of them in a later chapter.

We’ll split this chapter into the usual three parts:

  • The TLDR
  • The deep dive
  • The commands

Docker images - The TLDR

A Docker image is a unit of packaging that contains everything required for an application to run. This includes; application code, application dependencies, and OS constructs. If you have an application’s Docker image, the only other thing you need to run that application is a computer running Docker.

If you’re a former VM admin, you can think of Docker images as similar to VM templates. A VM template is like a stopped VM — a Docker image is like a stopped container. If you’re a developer you can think of...