Docker: Up & Running, 3rd Edition

Foreword

Containers are ubiquitous. From local development, to continuous integration, to managing large-scale production workloads, containers are everywhere. Why did this come about, where is it going, and what do you, the reader, need to know about this revolution that has taken over our industry?

Many older technologies offer the promise of “write once, run anywhere.” However, not all runtimes offered this facility, and even those that did still required the runtime (and any additional dependencies) to be available in order for an application to run. Containers offer the promise of “build once, run anywhere.” They allow you to package your applications, the runtime required to run it, configuration files, and any and all file dependencies it needs into one artifact. As long as you have a container runtime on the target machine, your application just works. This allows your infrastructure to be truly application agnostic. “It works on my machine,” begone!

Containers offer a standard application programming interface (API) to manage the lifecycle of a container and the applications packaged within the container. This API provides a homogenous interface to an otherwise heterogeneous deployment landscape, relieving operations teams from having to know the nitty-gritty of deploying and running applications and, consequently, being able to focus on the what they do best—managing infrastructure, enforcing security and compliance, and keeping the lights on.

This interface also forms ...