Nginx Configuration Basics

Configuration File Structure

Nginx uses a hierarchical configuration with contexts:

# Main context (global settings)
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Events context (connection handling)
events {
    worker_connections 1024;
    multi_accept on;
}

# HTTP context (web server settings)
http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # Logging
    log_format main '$remote_addr - $remote_user [$time_local] "$request" '
                    '$status $body_bytes_sent "$http_referer" '
                    '"$http_user_agent"';

    access_log /var/log/nginx/access.log main;

    # Performance
    sendfile on;
    tcp_nopush on;
    keepalive_timeout 65;
    gzip on;

    # Include site configurations
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

Key Directives

Worker Processes

# Auto-detect CPU cores (recommended)
worker_processes auto;

# Or set manually
worker_processes 4;

Worker Connections

events {
    # Max connections per worker
    worker_connections 1024;

    # Accept multiple connections at once
    multi_accept on;

    # Use efficient event method
    use epoll;  # Linux
    # use kqueue;  # FreeBSD/macOS
}

Logging

# Error log with level
error_log /var/log/nginx/error.log warn;

# Access log with format
access_log /var/log/nginx/access.log main;

# Disable access log for performance
access_log off;

# Buffer access logs
access_log /var/log/nginx/access.log main buffer=16k flush=5m;

Testing Configuration

# Test syntax
nginx -t

# Test and show config
nginx -T

# Reload without downtime
nginx -s reload
# Or: systemctl reload nginx

# Reopen log files
nginx -s reopen

Common Signals

# Graceful shutdown
nginx -s quit

# Fast shutdown
nginx -s stop

# Reload configuration
nginx -s reload

# Reopen log files (for rotation)
nginx -s reopen