4. [Step 4 - Install and Configure Nginx as a Reverse proxy][4]
5. [Step 5 - Testing][5]
6. [Links][6]
pm2 is a process manager for Node.js applications, it allows you to keep your apps alive and has a built-in load balancer. It's simple and powerful, you can always restart or reload your node application with zero downtime and it allows you to create a cluster of your node app.
In this tutorial, I will show you how to install and configure pm2 for the simple 'Express' application and then configure Nginx as a reverse proxy for the node application that is running under pm2.
**Prerequisites**
* Ubuntu 16.04 - 64bit
* Root Privileges
### Step 1 - Install Node.js LTS
In this tutorial, we will start our project from scratch. First, we need Nodejs installed on the server. I will use the Nodejs LTS version 6.x which can be installed from the nodesource repository.
Install the package '**python-software-properties**' from the Ubuntu repository and then add the 'nodesource' Nodejs repository.
When the installation succeeded, check node and npm version.
node -v
npm -v
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### Step 2 - Generate Express Sample App
I will use simple web application skeleton generated with a package named '**express-generator**' for this example installation. Express-generator can be installed with thenpm command.
Install '**express-generator**' with npm:
npm install express-generator -g
**-g:**install package inside the system
We will run the application as a normal user, not a root or super user. So we need to create a new user first.
Create anew user, I name mine '**yume**':
useradd -m -s /bin/bash yume
passwd yume
Login to the new user by using su:
su - yume
Next, generate a new simple web application with the express command:
express hakase-app
The command will create new project directory '**hakase-app**'.
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Go to the project directory and install all dependencies needed by the app.
cd hakase-app
npm install
Then test and start a new simple application with the command below:
DEBUG=myapp:* npm start
By default, our express application will run on port**3000**. Now visit server IP address:[192.168.33.10:3000][12]
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The simple web application skeleton is running on port 3000, under user 'yume'.
### Step 3 - Install pm2
pm2 is a node package and can be installed with thenpm command. So let's install it with npm(with root privileges, when you are still logged in as user hakase, then run the command "exit" ro become root again):
npm install pm2 -g
Now we can use pm2 for our web application.
Go to the app directory '**hakase-app**':
su - hakase
cd ~/hakase-app/
There you can find a file named '**package.json**', display its content with the cat command.
You can see the '**start**' line contains a command that is used by Nodejs to start the express application. This command we will use with the pm2 process manager.
Run the express application with the pm2 command below:
pm2 start ./bin/www
Now you can see the results is below:
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Our express application is running under pm2 with name '**www**', id '**0**'. You can get more details about the application running under pm2 with the show option '**show nodeid|name**'.
pm2 show www
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If you like to see the log of our application, you can use the logs option. It's just access and error log and you can see the HTTP Status of the application.
It will generate the systemd configuration file for application startup. When you reboot your server, the application will automatically run on startup.
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### Step 4 - Install and Configure Nginx as a Reverse proxy
In this tutorial, we will use Nginx as a reverse proxy for the node application. Nginx is available in the Ubuntu repository, install it with the apt command:
sudo apt-get install -y nginx
Next, go to the '**sites-available**' directory and create a new virtual host configuration file.
