Nginx Installation

Nginx Installation

Nginx (pronounced "engine-x") is an event-driven web server and reverse proxy. Unlike Apache's process-per-connection model, Nginx uses asynchronous non-blocking I/O to handle thousands of concurrent connections with very low memory overhead. This makes Nginx the preferred choice for serving static files at high traffic volumes and as a reverse proxy in front of application servers. On Ubuntu, you can install Nginx from the Ubuntu repository (slightly older) or from the official Nginx repository (latest stable).

Nginx architecture

Nginx process model:
  Master process (root, reads config, manages workers)
    ├── Worker 1 (handles thousands of connections via epoll)
    ├── Worker 2 (usually 1 worker per CPU core)
    └── Worker N

  vs Apache:
  Apache (prefork):  1 connection = 1 process (memory-intensive)
  Apache (worker):   1 connection = 1 thread
  Nginx:             1 worker = 1000s of connections (event loop)

Installing Nginx

# Option 1: Ubuntu repository (easier, slightly older version)
sudo apt update
sudo apt install -y nginx

# Option 2: Official Nginx repository (latest stable)
curl -fsSL https://nginx.org/keys/nginx_signing.key | sudo apt-key add -
echo "deb http://nginx.org/packages/ubuntu $(lsb_release -cs) nginx" | sudo tee /etc/apt/sources.list.d/nginx.list
sudo apt update && sudo apt install -y nginx

# Verify installation:
nginx -v
systemctl status nginx
curl -I http://localhost

nginx -v output

nginx version: nginx/1.24.0

sudo ufw allow 'Nginx Full'    # Allow ports 80 and 443

Configuration structure

# Nginx config layout:
# /etc/nginx/nginx.conf               ← main config (global settings)
# /etc/nginx/conf.d/*.conf            ← server blocks (load order by name)
# /etc/nginx/sites-available/         ← Ubuntu-style site configs
# /etc/nginx/sites-enabled/           ← symlinks to enabled sites

cat /etc/nginx/nginx.conf

Key sections of nginx.conf

worker_processes auto;              # auto = one worker per CPU core

events {
    worker_connections 1024;        # max connections per worker
}

http {
    include /etc/nginx/mime.types;
    server_tokens off;              # hide version in headers/error pages

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

Managing Nginx

# Test configuration syntax (always before reload):
sudo nginx -t

nginx -t output

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl reload nginx     # Graceful reload (preferred)
sudo systemctl restart nginx    # Full restart

# Check error log:
sudo tail -f /var/log/nginx/error.log

Nginx vs Apache: which to choose

Conclusion

After installing Nginx, immediately set server_tokens off; in nginx.conf to hide the version string from HTTP headers and error pages. Then create your first server block in /etc/nginx/sites-available/, enable it with a symlink to sites-enabled/, test with nginx -t, and reload. The Nginx documentation is excellent — the official docs at nginx.org explain each directive with context that the Ubuntu manpages lack.