Installing, Files and Controlling NGINX

Where things live and how to change them safely

Install from your distribution (apt install nginx, dnf install nginx) or, for newer versions, from the official nginx.org repositories; the official Docker image nginx is common in containers. Key locations on Debian and Ubuntu: main configuration /etc/nginx/nginx.conf; site configurations in /etc/nginx/sites-available/ linked into /etc/nginx/sites-enabled/ (distribution convention), or /etc/nginx/conf.d/*.conf (the convention in official packages); logs in /var/log/nginx/; default content in /usr/share/nginx/html or /var/www/html. Always test before applying: nginx -t checks syntax and file references, and nginx -T prints the whole merged configuration, very useful for debugging includes. Apply changes with a graceful reload (nginx -s reload or systemctl reload nginx): the master starts new workers with the new configuration while old workers finish their in-flight requests, so there is no downtime. A full restart drops connections and is rarely needed.

Everyday control commands

Test, inspect and reload without dropping connections.

sudo nginx -t                    # syntax and file checks
sudo nginx -T | less             # full effective configuration, all includes expanded
sudo systemctl reload nginx      # graceful: new workers, old ones finish requests
sudo systemctl status nginx
nginx -v                         # version
nginx -V 2>&1 | tr ' ' '\n' | grep -- --with   # compiled-in modules

# Docker
docker run -d -p 8080:80 -v "$PWD/site:/usr/share/nginx/html:ro" nginx:stable

Changing the menu without closing the restaurant

A graceful reload is like printing new menus: tables already eating finish with the old menu, and new guests get the new one. Nobody is asked to leave halfway through a meal.

Quick check: What does `nginx -s reload` do?

• Stops NGINX immediately and starts it again
• Only checks syntax
• Clears all logs
• Starts workers with the new configuration while old workers finish in-flight requests