Deploying production-ready Node.js Apps with PM2 and Nginx

The Problem with npm start

When developers rent their first Ubuntu VPS, they typically clone their GitHub repository, run npm install, and then execute npm start.

The app works brilliantly—until the developer closes their SSH terminal. Suddenly the process dies, and the website shows a 502 Bad Gateway. Even if you use nohup, what happens if there's a memory leak and your Node instance crashes? It won't restart on its own.

Meet PM2 (Process Manager 2)

PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, reload them without downtime, and manage application logging.

Step 1: Install Node & PM2 Globally

SSH into your server and install the long-term support version of Node.js:

curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash -
sudo apt install -y nodejs

Now, install PM2 globally:

sudo npm install pm2@latest -g

Step 2: Start Your Application

Navigate to your project folder (which you already cloned). If you are running an Express API:

pm2 start app.js --name "my-backend-api"

If you are running a built Next.js application:

pm2 start npm --name "nextjs-frontend" -- start

Step 3: Configure Startup Scripts

If AmanaFlow reboots your server for a kernel update, your PM2 instances won't start automatically unless you freeze their state. Run this command and follow the instructions output on the terminal:

pm2 startup

Then, save your current list of running apps:

pm2 save

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Step 4: The Reverse Proxy (Nginx)

Your Node app is now running on a port (e.g., localhost:3000). We need to use Nginx to map port 80/443 (the public web) to port 3000.

Create an Nginx configuration file:

server {
    listen 80;
    server_name 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_cache_bypass $http_upgrade;
    }
}

Reload Nginx, configure SSL via Certbot, and your Node environment is completely robust.

FAQs

Q: Does PM2 do load balancing?
A: Yes! You can run pm2 start app.js -i max to spawn a separate Node process for every physical CPU core on your AmanaFlow VPS, instantly load-balancing incoming traffic across all cores.