12: Docker overlay networking

Overlay networks are at the center of most cloud-native microservices apps. In this chapter we’ll get you up-to-speed with overlay networking on Docker.

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 reliably and securely, even when they’re on different hosts that are on different networks. This is where overlay networks come into play. They create a flat, secure, layer 2 networks spanning multiple hosts. Containers on different hosts can connect to the same overlay network and communicate directly.

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