Networking

Why Tune the Linux Network Stack The Linux kernel’s default network parameters are designed for general-purpose scenarios — conservative and safe. However, under high-concurrency web services, large-scale load balancers, CDN nodes, and similar workloads, these defaults become bottlenecks. Typical symptoms include: dmesg showing nf_conntrack: table full, dropping packet ss -s showing a large number of TIME-WAIT connections During load testing, CPU is not saturated but throughput plateaus NIC PPS (packets per second) is far below hardware capability Most of these issues stem from untuned kernel network parameters....

Four Core Requirements of the Kubernetes Networking Model The Kubernetes networking model is built on four core requirements. Understanding them is the foundation for mastering K8s networking. According to the official Kubernetes networking model documentation, these four requirements form the cornerstone of cluster network communication. 1. Pod-to-Pod Communication K8s requires that all Pods can communicate directly via IP without NAT (Network Address Translation). This means: Each Pod has its own IP address Pod-to-Pod communication uses real Pod IPs, without NAT translation Regardless of which Node a Pod is scheduled on, the Pod-to-Pod network remains flat and reachable This is the most fundamental design decision in the K8s networking model....

Overview Kubernetes Service provides Layer 4 load balancing, but in production, most web applications need Layer 7 routing capabilities: domain-based virtual hosting, path-based routing, TLS termination, and canary deployments. Ingress is K8s’s abstraction for Layer 7 routing, and the Ingress Controller is the concrete implementation of this abstraction. Choosing an Ingress Controller is not a small decision—it sits at the entry point of all external traffic. A wrong choice or misconfiguration can impact the availability of the entire cluster’s services....