34. Kubernetes network principles - basic concepts

This chapter explains the knowledge points

• 1. Kubernetes network model
• 2. network namespace
• 3. veth device pair
• 4. bridge
• 5. iptables 和 netfilter
• 6. routing
• 7. Docker's network implementation
• 8. Limitations of docker networking

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1. Kubernetes network model

Kubernetes' network model is designed to simplify network configuration in container orchestration and provide a way for containers to communicate directly. The core principle of this network model is that each Pod has an independent IP address, and all Pods are in a flat, directly connected network space . This means that regardless of which node the Pods are running on, they are directly reachable via each other's IPs. The design of this principle makes it unnecessary for users to think about how to establish connections between Pods, or how to map container ports to host ports.

In Kubernetes, IP addresses are allocated in units of Pods, which means that all containers inside each Pod share the same network stack, which is equivalent to being in a network namespace . In this model, each Pod has a unique IP address, also known as the IP-per-Pod model.

Since the network model of Kubernetes assumes Po