Nginx Cheatsheet

Nginx is a high-performance web server, reverse proxy, load balancer, and HTTP cache.

Installation

# Debian / Ubuntu
sudo apt install nginx
 
# RHEL / CentOS / Arch Linux
sudo dnf install nginx
sudo pacman -S nginx

Service Management

sudo systemctl enable --now nginx
sudo systemctl status nginx
sudo systemctl restart nginx
sudo systemctl reload nginx   # Gracefully reload configuration without dropping connections

Configuration File Locations

Main Config: /etc/nginx/nginx.conf
Server Blocks (Virtual Hosts):
- Ubuntu/Debian: /etc/nginx/sites-available/ (symlinked to /etc/nginx/sites-enabled/)
- RHEL/CentOS: /etc/nginx/conf.d/
Document Root: /var/www/html/ or /usr/share/nginx/html/

Testing Configuration Syntax

Always test your configuration before reloading Nginx.

sudo nginx -t
# Output should say:
# nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
# nginx: configuration file /etc/nginx/nginx.conf test is successful

Basic Server Block (Static Website)

Create a file at /etc/nginx/sites-available/example.com:

server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;
 
    root /var/www/example.com/html;
    index index.html index.htm;
 
    location / {
        try_files $uri $uri/ =404;
    }
 
    error_page 404 /404.html;
    error_page 500 502 503 504 /50x.html;
}

Enable it (Ubuntu/Debian) by creating a symlink:

sudo ln -s /etc/nginx/sites-available/example.com /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

Nginx as a Reverse Proxy

Nginx is commonly used to proxy requests to backend application servers (like Node.js, Python, or Java).

server {
    listen 80;
    server_name api.example.com;
 
    location / {
        proxy_pass http://localhost:3000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_cache_bypass $http_upgrade;
    }
}

Logs

tail -f /var/log/nginx/access.log
tail -f /var/log/nginx/error.log

Cheatsheets