Kubernetes Networking

Pod Networking on a Single Node

Two pods on the same node talk to each other. No overlay, no routing protocol, no cloud involvement. Understanding this simplest case gives you the vocabulary for every harder one.

What this lesson covers

  • How a pod gets an interface, and what sits on the host side of it
  • The pod's own routing table and what it can see
  • Reaching another pod on the same node, and where the boundary between pod and host actually is
  • The kernel primitives underneath are covered in Container Internals and Runtime Engineering and are referenced rather than re-taught here

What is actually happening

Coming soon.

The Kubernetes model versus the CNI's choice

Coming soon.

How it works in practice

Coming soon.

Common failure modes

Coming soon.

What people get wrong

Coming soon.

INTERVIEW QUESTION

Trace a packet from one pod to another on the same node. What does the pod see, what does the host see, and where is the boundary between them?