Welcome to this guide on deploying a Node.js app on a Virtual Private Server (VPS). Whether you prefer to have control over your deployment environment or simply enjoy the hands-on experience, using a VPS is a powerful choice. In this tutorial, we'll go through the process step by step.

So, let's begin.

Step 1 - Install Nodejs

Let's download nodejs from Nodesource. NodeSource is a company which provides enterprise-grade Node support and maintains a repository containing the latest versions of Node.js.

curl -sL https://deb.nodesource.com/setup_16.x | sudo -E bash -

Let's install nodejs now:

sudo apt-get install -y nodejs

Check the installation of node and npm using the following commands:

node --version && npm --version

You will see the versions of nodejs and npm

Step 2 - Creating a sample nodejs file

Before deploying a real application, let's create a simple Node.js app for demonstration purposes:

sudo nano app.js

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('Hello World!')
})

app.listen(port, () => {
  console.log(`Example app listening at http://localhost:${port}`)
})

Lets now install express so that we can run this app server:

npm install express

let's test the app.

node app.js

Visit http://server-ip:3000 to see the "hello world" page.

Step 3 - Using a Process Manager

To ensure your application runs continuously, even if issues arise, we'll use pm2 as a process manager.

Install and start the application using the following commands:

sudo npm i pm2 -g

Start the application using the following command:

pm2 start app.js

Step 4 - Configuring Reverse proxy

To simplify access to your app and enhance security, configure Nginx as a reverse proxy.

Install Nginx and create a configuration file for your Node.js app:

sudo apt install nginx

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

Copy the following content to the conf file:

server{
  server_name <<ENTER YOUR SERVER ADDRESS HERE>>;

      location / {
        proxy_pass http://localhost:<<PORT USED BY APP>>;
        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;
    }
}

Activate the configuration:

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

Visit http://your-ip/ to see your application working seamlessly.

Conclusion:

Congratulations! You've successfully deployed a Node.js app on your VPS using NodeSource, pm2 as a process manager, and Nginx as a reverse proxy. Keep in mind that the sample app used here is not suitable for production. Always deploy production-ready applications, considering factors like scalability and security.

Happy coding!