Nginx Troubleshooting & Fix Guides

Diagnose and fix Nginx 502 Bad Gateway errors when proxying to upstream backends — check sockets, timeouts, and upstream health.

Resolve Nginx 'Too many open files' errors by increasing worker_rlimit_nofile, system ulimits, and kernel file descriptor limits.

How to use Apache httpd as a reverse proxy with mod_proxy — proxying to backend services, load balancing across multiple upstreams, WebSocket proxying, and health check configuration.

How to configure Apache httpd for production use — name-based virtual hosts, SSL/TLS with Let's Encrypt, HTTP to HTTPS redirects, mod_rewrite rules, and performance tuning with MPM.

An introduction to Envoy Proxy's architecture — listeners, clusters, filters, and the xDS dynamic configuration API. Covers static configuration for standalone use and how Envoy fits into service meshes like Istio.

Advanced Envoy traffic management — configuring retries with exponential backoff, per-request timeouts, weighted canary routing, global rate limiting, and fault injection for resilience testing.

Advanced HAProxy SSL configuration — multi-domain SNI routing from a single frontend, mutual TLS (mTLS) for service-to-service authentication, certificate management, and OCSP stapling.

A comprehensive HAProxy configuration guide covering frontends, backends, balance algorithms, active health checks, SSL termination, ACLs, rate limiting, and the runtime socket API.

Step-by-step guide to building a highly available load balancer pair with HAProxy and Keepalived — covering the full stack from VIP configuration to health checks, stats, and SSL termination.

How to configure Keepalived for automatic failover using VRRP — setting up master/backup pairs, virtual IPs, health-check scripts, and combining it with HAProxy or Nginx for zero-downtime load balancer HA.

Configure Nginx upstream load balancing with round robin, least connections, and IP hash strategies including health checks and failover.

Implement Nginx rate limiting using limit_req and limit_conn to protect APIs from abuse, brute force, and traffic spikes in production.

Security headers and configuration reference — copy-paste snippets for Nginx, Kubernetes Ingress, Cloudflare, and Helmet.js.

Set up Nginx as a reverse proxy with SSL termination, response caching, rate limiting, and load balancing for high-traffic applications.

A practical comparison of Kubernetes Ingress and Gateway API, with a migration strategy that won't take down your production traffic.