12: Docker overlay networking

Overlay networks are at the beating heart of many cloud-native microservices apps. In this chapter we’ll cover the fundamentals of native Docker overlay networking.

Docker overlay networking on Windows has feature parity with Linux. This means the examples we’ll use in this chapter will all work on Linux and Windows.

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

• The TLDR
• The deep dive
• The commands

Let’s do some networking magic.

Docker overlay networking - The TLDR

In the real world, it’s vital that containers can communicate with each other reliably and securely, even when they’re on different hosts that are on different networks. This is where overlay networking comes in to play. It allows you to create a flat, secure, layer-2 network, spanning multiple hosts. Containers connect to this and can communicate directly.

Docker offers native overlay networking that is simple to configure and secure...