After reading the previous chapters, you should be familiar on how to find images suitable as a base for your own software. You can pull them from the remote repository, run and make changes to them during runtime and then export as new images. We saw building our own image earlier via running a container, installing our software in it, and doing a commit to create the image in Chapter 3, Understanding Images and Containers. This is not very practical and sometimes very cumbersome. Luckily, there's a solution for that. Docker has a scripting engine that we can use to create a new image with a predefined list of instructions and properties. We call these scripts Dockerfiles. This time, we are going to create an image based on a Dockerfile. This chapter will cover the following topics:
Introduction to Dockerfiles
Creating and editing Dockerfiles
Dockerfile instructions
Building images
Let's understand what a Dockerfile is first. It's nothing more than a plain text file...