2 The Kubernetes Networking Model

Kubernetes makes opinionated choices about how Pods are networked. In particular, Kubernetes dictates the following requirements on any networking implementation:

• all Pods can communicate with all other Pods without using network address translation (NAT).
• all Nodes can communicate with all Pods without NAT.
• the IP that a Pod sees itself as is the same IP that others see it as.

Given these constraints, we are left with four distinct networking problems to solve:

1. Container-to-Container networking
2. Pod-to-Pod networking
3. Pod-to-Service networking
4. Internet-to-Service networking