Nginx Rate Limit Burst Exceeded

Introduction

Nginx rate limiting rejects requests when burst and nodelay configuration is too restrictive. This guide provides step-by-step diagnosis and resolution with specific commands and configuration examples.

Symptoms

Typical symptoms and error messages when this issue occurs:

bash

Load balancer error: backend unavailable
Check health check configuration
Verify backend server status

Observable indicators: - Load balancer returns 5xx errors to clients - Backend servers marked as unhealthy - Traffic not reaching expected backends

Common Causes

1.Nginx load balancer issues are typically caused by:
2.Upstream server configuration errors
3.Health check not enabled or misconfigured
4.Proxy timeout values too low
5.Missing or incorrect resolver for dynamic backends

Step-by-Step Fix

Step 1: Check Current State

bash

nginx -t && nginx -T | grep upstream

Step 2: Identify Root Cause

bash

curl -s localhost/nginx_status

Step 3: Apply Primary Fix

bash

# Primary configuration fix
upstream backend {
    server 10.0.0.1:8080;
    server 10.0.0.2:8080;
    keepalive 32;
}

Apply this configuration and reload the load balancer.

Step 4: Apply Alternative Fix (If Needed)

bash

# Alternative fix: adjust timeouts
proxy_connect_timeout 10s;
proxy_read_timeout 60s;
proxy_send_timeout 60s;

Step 5: Verify the Fix

After applying the fix, verify with:

bash

curl -s http://localhost/nginx_status && tail -10 /var/log/nginx/access.log

Expected output should show healthy backends and successful request routing.

Common Pitfalls

Forgetting proxy_http_version 1.1 for keepalive
Health check not enabled in OSS version
DNS cache causing stale upstream IPs
Weight ignored with IP hash method

Best Practices

Use keepalive for connection pooling
Configure appropriate proxy timeouts
Enable health checks with zones
Use resolver for dynamic upstream DNS