A comprehensive guide to Kubernetes networking fundamentals, covering the IP-per-Pod model, flat network structure, CNI plugins, and how packets move between pods on the same and different nodes. The guide explains Kubernetes service types (ClusterIP, NodePort, LoadBalancer, ExternalName, Headless), service discovery via cluster DNS, and virtual IPs. A significant portion focuses on Cilium as a CNI, detailing how it uses eBPF to replace iptables/kube-proxy for higher performance, identity-based security, transparent encryption, and observability via Hubble. Native routing vs. overlay/encapsulation modes are compared with trade-offs discussed.
Table of contents
Building BlocksLayer 1: Intra-Node NetworkingLayer 2: Inter-Node NetworkingService TypesCluster DNSService DiscoveryVirtual IPs and Service ProxiesHow Cilium Optimizes Service Discovery?Sort: