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Setting Up Nginx with systemd Service Files on Linux

Nihesh Rachakonda•
nginxlinuxsystemdreverse-proxydeployment

Nginx is a high-performance web server and reverse proxy widely used in production systems. This guide walks through installing Nginx, configuring it, and understanding its systemd service files.

What is Nginx?

Nginx is:

  • A web server
  • A reverse proxy
  • A load balancer
  • An SSL termination layer

It is commonly used to expose backend applications running on ports like 3000, 4000, etc.

Prerequisites

  • Ubuntu / Debian based Linux
  • Root or sudo access
  • A running backend/frontend/DB service (Node.js, Next.js, API, etc.)
  • Optional: Domain name

Step 1: Install Nginx

Update the system and install Nginx:

sudo apt update
sudo apt install nginx -y

Check if it's running:

sudo systemctl status nginx

Open your server IP in the browser — you should see the Nginx welcome page.

Step 2: Understanding Nginx File Structure

Important paths:

/etc/nginx/
├── nginx.conf
├── sites-available/
├── sites-enabled/
├── conf.d/
└── modules-enabled/
  • sites-available → All virtual host configs
  • sites-enabled → Active configs (symlinks)
  • nginx.conf → Main configuration file

Step 3: Create a Reverse Proxy Config

Create a new site config:

sudo nano /etc/nginx/sites-available/myapp

Paste this configuration:

server {
    listen 80;
    server_name your-domain.com;

    location / {
        proxy_pass http://127.0.0.1:3000;
        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_set_header X-Forwarded-Proto $scheme;
    }
}

Replace:

  • your-domain.com with your actual domain
  • 3000 with your service port

Step 4: Enable the Site

Create a symlink:

sudo ln -s /etc/nginx/sites-available/myapp /etc/nginx/sites-enabled/

Test configuration:

sudo nginx -t

Reload Nginx:

sudo systemctl reload nginx

Step 5: Common systemctl Commands

sudo systemctl start nginx
sudo systemctl stop nginx
sudo systemctl restart nginx
sudo systemctl reload nginx
sudo systemctl enable nginx
sudo systemctl disable nginx

Check logs:

journalctl -u nginx -f

Step 6: Custom Error Pages (Optional)

Create an error page:

sudo nano /var/www/html/50x.html

Example HTML content:

<h1>Service Temporarily Unavailable</h1>
<p>Please try again later.</p>

Add to your server block:

error_page 502 503 504 /50x.html;

location = /50x.html {
    root /var/www/html;
}

Reload Nginx:

sudo systemctl reload nginx

Step 7: Firewall Configuration

sudo ufw allow 'Nginx Full'
sudo ufw reload

Important: Be careful not to lose your SSH access when configuring firewall rules!

Common Issues & Fixes

Bad Gateway (502)

Common causes:

  • Backend service not running
  • Wrong port in proxy_pass
  • App bound to localhost incorrectly

Config Not Loading

Always test your configuration before reloading:

sudo nginx -t

This will check for syntax errors in your Nginx configuration files.

Conclusion

Nginx is a powerful tool that transforms your application from a localhost project into a production-ready service. With reverse proxy configuration and systemd management, you can serve your apps securely, scale efficiently, and handle failures gracefully.

Whether you're deploying a Next.js app, a Node.js API, or any web service — mastering Nginx is essential for modern deployment workflows. Keep experimenting, monitor your logs, and your deployments will become second nature!

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