Kubernetes networking essentials

Without exaggeration, K8s networking is probably the hardest part to understand, and even for very experienced engineers and operators, it might be tough. As you hopefully remember from Chapter 4, Kubernetes implements the Container Networking Interface (CNI), which allows us to use different overlay network plugins for container networking. Yet there are so many CNI providers out there (Flannel, Calico, Cilium, Weave, and Canal, to name a few) that it is easy to get confused. Those providers rely on different technologies such as Border Gateway Protocol (BGP) or Virtual Extensible LAN (VXLAN) to deliver different levels of overlay network performance and offer different features.

But don’t worry – for the scope of KCNA, you are not required to know many details. For now, we will cover Kubernetes networking essentials.

Have a look at the following diagram:

Figure 8.1 – Kubernetes networking model...