Learning by practicing
I started playing with docker a while ago, and like most people I was instantly impressed with its power and ease of use. Simplicity is one of docker’s core tenants, and much of docker’s power is abstracted behind simple cli commands. As I was learning to use docker, I wanted to know what it was doing in the background to make things happen, especially around networking (one of my primary areas of interest).
I found numerous documentation for how to create and manipulate container networks, but not as many when it came to how docker makes container networking work. Docker extensively uses linux iptables and bridge interfaces, and this post is my summary of how that is used to create container networks. Most of this information came from github discussion threads, presentations, as well as my own testing, and I link to a number of helpful resources at the end of this post.
I used docker 1.12.3 for the examples in this post. This is not meant as a comprehensive description of docker networking nor as an introduction to docker networking. I hope it might add some insights for users, and I would appreciate any feedback or comments on errors or anything missing.
