Kubernetes Topology Aware Routing Technical Guide

This technical guide examines the concept of Kubernetes Topology Aware Routing and its role in enhancing network performance across multiple availability zones (AZs) in Kubernetes clusters. As deployments increasingly occur in multi-AZ environments, maintaining traffic within the originating zone is critical for minimizing latency and reducing data transfer costs. The guide outlines how Topology Aware Routing operates by considering the network and geographic topology of the cluster to route traffic more efficiently. It details the basic routing policy of Kubernetes, which typically distributes traffic equally across nodes, and explains the benefits of Topology Aware Routing, including reduced latency, network cost savings, improved availability, and guaranteed data locality. Additionally, the document provides configuration methods for enabling Topology Aware Routing, including the necessary annotations for Kubernetes services and ingress-nginx pods. The guide also describes the principles of operation, including topology hints and EndpointSlices, which optimize traffic routing based on endpoint proximity.