Basics of Docker - Files, Images, & Containers

Docker

Let's start off with a common question, what exactly is Docker? In textbook terms, Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. That probably means nothing to you so let's simplify it and break it down for you. In simple terms Docker allows you to recreate an operating system or the software environment your program runs in. That means you no longer have to worry about a program not working on another machine when it works natively on yours. It's also this environment recreation that gives the most headaches as you'll find out in later chapters.

Dockerfiles

As I've alluded to earlier Docker allows you to replicate the environment your program runs in, so that begs the question, how exactly am I supposed to do that? First things first you'll need Docker to run Docker, if you're on Windows or Mac you'll be basically forced to use Docker Desktop, if you're on Linux I recommend you install Lazy Docker. If its native documentation is confusing you can watch and follow this guide starting at 18:09 or email me at [email protected]. Other than that you'll need code editing software such as Visual Studio Code (VS Code). Be sure to install the Docker extensions if you're going with VS Code. 

That's it for the prerequisites let's get into how to actually create a docker file. The basic format of any docker file consists of the following elements: FROM, WORKDIR, RUN, COPY, and CMD.