Deploying Node.js applications with PM2 on Vultr

1. Sign up and log in to the Vultr Customer Portal.
2. Navigate to the Products page.
3. From the side menu, select Compute.
4. Click the Deploy Server button in the center.
5. Select Cloud Compute as the server type.
6. In the "Server Location" section, select the region of your choice.
7. In the "Server Image" section, click the Marketplace Apps tab and select the NodeJS image. The NodeJS Marketplace App comes pre-installed with the latest Node.js and Node Package Manager (npm) binaries, allowing you to save setup time.
8. In the "Server Size" section, select the server size as per requirement.
9. Select any more features as required in the "Additional Features" section.
10. Click the Deploy Now button on the bottom right corner.

Having created a Vultr server as described previously, this section will guide you through creating a sample Node.js application using Express. We will walk you through initializing a Node.js project, installing Express, and creating a basic endpoint. If you already have an existing Node.js application, feel free to skip this part, clone your Git repository, and continue from the next section.

1. Create a folder to store the project files, and navigate into it.
   bash

   mkdir ~/express-demo
   cd ~/express-demo
   

2. Initialize a Node.js project.
   bash

   npm init
   

3. Install the express library.
   bash

   npm install express
   

4. Create a file named index.js.
   bash

   nano index.js
   

5. Paste the following content into the index.js file.
   javascript

   const express = require("express");
   const app = express();
   
   app.get("/", (req, res) => {
     res.send("<h1>Hello World, greetings from Vultr</h1>");
   });
   
   app.listen(3000, () => {
     console.log("Server listening on port 3000");
   });
   

   The code block above defines a basic Express-based application that displays the "Hello World, greetings from Vultr" message when you visit the home page.
6. Save the file, and exit the editor.
7. Allow port 3000 to listen for incoming connections.
   bash

   sudo ufw allow 3000
   

8. Start the application.
   bash

   node index.js
   

9. In a web browser, navigate to the URL as shown below.

   http://SERVER_IP:3000
   

   After you confirm access, you may stop the server.

PM2 provides an an easy-to-use CLI interface to ensure that your services are persistent, reliable, and restart automatically. In this section, you'll learn how to install the PM2 package, start your application in cluster mode, and set up a persistent service to ensure that your application starts automatically when the server boots up.

1. Install PM2 globally. The -g flag specifies that the PM2 package should be installed globally, making it accessible to all system users.
   bash

   sudo npm install pm2 -g
   

2. Start your Node.js application in cluster mode. Make sure to replace the path with your application's actual location. The -i flag specifies that the Node.js application should run with four instances in cluster mode.
   bash

   pm2 start ~/express-demo -i 4 --name express-demo
   

3. Set up a persistent service.
   bash

   pm2 startup
   

4. Save the configuration to apply the changes.
   bash

   pm2 save
   

Nginx acts as a reverse proxy between your web server and clients. It directs incoming requests based on your request configuration settings. In this section, you'll learn how to configure your example application for efficient request handling and load balancing using Nginx. You'll also learn how to configure your apps for reverse proxy.

1. Log in to the Vultr Customer Portal.
2. Navigate to the Products page.
3. From the side menu, expand the Network dropdown, and select DNS.
4. Click the Add Domain button in the center.
5. Follow the setup procedure to add your domain name by selecting the IP address of your server.
6. Set the following hostnames as your domain's primary and secondary nameservers with your the domain registrar:
   • ns1.vultr.com
   • ns2.vultr.com
7. Install Nginx.
   bash

   sudo apt install nginx
   

8. Create a file named express-demo.conf in the sites-available directory.
   bash

   sudo nano /etc/nginx/sites-available/express-demo.conf
   

9. Paste the following content into the express-demo.conf file. Make sure to replace example.com with your actual domain name.
   bash

   server {
        listen 80;
        listen [::]:80;
        server_name example.com www.example.com;
   
        location / {
            proxy_pass http://127.0.0.1:3000/;
        }
   }
   

   The following directives are used in the above virtual host configuration:
   • server defines a block of settings for your domain.
   • listen instructs the server to listen on port 80 for incoming requests.
   • server_name specifies the domain names to which this server block will respond.
   • location defines what the server should do with each incoming request.
   • proxy_pass instructs the server to forward requests to another location, in this case to http://127.0.0.1:3000/.
10. Save the file, and exit the editor.
11. To activate the virtual host configuration, create a soft link in the sites-enabled directory.
    bash

    sudo ln -s /etc/nginx/sites-available/express-demo.conf /etc/nginx/sites-enabled/
    

12. Test the configuration to identify the errors.
    bash

    sudo nginx -t
    

    If the configuration has no errors, your output should look like:
    bash

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

13. Restart the Nginx server.
    bash

    sudo systemctl reload nginx
    

14. Allow incoming connections on port 80.
    bash

    sudo ufw allow 80/tcp
    

15. In a web browser, navigate to the URL as shown below.

    http://example.com
    

16. Deny incoming connections on port 3000.
    bash

    sudo ufw deny 3000
    

Certbot allows you to acquire SSL certificates from "Let's Encrypt", a free certificate authority. These SSL certificates serve as cryptographic keys that enable secure communication between a user and a web server. In this section, you'll learn how to request a free SSL certification from "Let's Encrypt" for your domain and implement HTTPS for your application. You'll also learn how to set the certificate to auto-renew before it expires in 90 days.

1. Allow incoming connections on port 443 for HTTPS.
   bash

   sudo ufw allow 443/tcp
   

2. Install the certbot package using the snap package manager.
   bash

   sudo snap install --classic certbot
   

3. Request a new SSL certificate for your domain. Make sure to replace example.com with your actual domain name.
   bash

   sudo certbot --nginx -d example.com -d www.example.com
   

4. In a web browser, navigate to the URL as shown below

   https://example.com
   

5. Test that the SSL certificate auto-renews upon expiry.
   bash

   sudo certbot renew --dry-run
   

In this section, you'll learn how to scale your PM2 services both up and down. Additionally, you'll explore various other PM2 commands for monitoring your application processes.

List all the PM2 processes.

pm2 list

Example output:

To scale down your Node.js application, run the pm2 scale command as shown below. Make sure to replace express-demo with your actual service name.

pm2 scale express-demo 2

The above command reduces the instance count from the four instances running initially to two.

Example output:

To scale up your Node.js/Express application, run the pm2 scale command as shown below. Make sure to replace express-demo with your actual service name.

pm2 scale express-demo 5

The above command increases the instance count from the two instances running to five.

Example output:

• To stop all PM2 processes:
  bash

  pm2 stop all
  

• To restart all PM2 processes:
  bash

  pm2 restart all
  

• To soft-reload all PM2 processes:
  bash

  pm2 reload all
  

  Soft reloading helps to minimize downtime for your Node.js/Express application by reloading instances one by one.
• To monitor all PM2 processes:
  bash

  pm2 monit
  

• To examine the logs generated by PM2:
  bash

  pm2 logs
  

In this article, you learned how to deploy a Node.js application using PM2 on a Vultr Cloud Compute server. The tutorial guided you through the steps to create, scale, and monitor a PM2 service. You also learned how to set up Nginx as a reverse proxy server for your PM2 service and secure it with an SSL certificate.

As an extension of your Node.js deployment, consider using a Vultr Managed Database to host the database associated with your application. It provides a secure, highly available, and easily scalable database cluster that works right out of the box.

This is a sponsored article by Vultr. Vultr is the world's largest privately-held cloud computing platform. A favorite with developers, Vultr has served over 1.5 million customers across 185 countries with flexible, scalable, global Cloud Compute, Cloud GPU, Bare Metal, and Cloud Storage solutions. Learn more about Vultr.