HOW TO: Install and configure Node.js

This article describes how to install the Node.js platform. You can use Node.js to host third-party applications or you can run your own applications.

INSTALLATION PREREQUISITES

There are two prerequisites for running Node.js on a server:

Your account must have the normal shell (not jailshell) enabled. To determine which shell your account is using, log in using SSH, and then type the following command:
```
echo $SHELL
```
Node.js currently only works on servers running CentOS 6 or CentOS 7. To determine the CentOS version on your server, log in to your account using SSH, and then type the following command:
```
uname -r
```
If the output from this command contains el6 (for example, 2.6.32-531.17.1.lve1.2.60.el6.x86_64) or el7 (for example, 3.10.0-714.10.2.lve1.5.12.el7.x86_64) , then your server is running CentOS 6 or CentOS 7. However, if you see el5h (for example, 2.6.32-531.23.3.lve1.2.66.el5h.x86_64), then your server is running CentOS 5 and does not support Node.js.

INSTALLING NODE.JS AND NPM

After you determine that your account meets the installation prerequisites, you can download and install Node.js and npm (the Node.js package manager). To do this, follow these steps:

Log in to your server using SSH.
At the command prompt, type the following commands:
```
cd ~
wget https://nodejs.org/dist/v4.4.1/node-v4.4.1-linux-x64.tar.xz
```
This command downloads the binaries for the Node.js version 4.4.1 LTS (long-term support) release. If you download a newer development version of Node.js, change the version numbers in the following commands to match the version you downloaded.
To extract the Node.js files, type the following command:
```
tar xvf node-v4.4.1-linux-x64.tar.xz
```
Rename the extracted folder to the more convenient nodejs name, type the following command:
```
mv node-v4.4.1-linux-x64 nodejs
```
To install the node and npm binaries, type the following commands:
```
mkdir ~/bin
cp nodejs/bin/node ~/bin
cd ~/bin
ln -s ../nodejs/lib/node_modules/npm/bin/npm-cli.js npm
```
After you run these commands, Node.js and npm are installed on your account. To verify this, type the following commands:
```
node --version
npm --version
```

STARTING A NODE.JS APPLICATION

After you install Node.js, you are ready to run Node.js applications. However, the exact steps to do this vary depending on the application configuration.

Method #1: Use npm

Many third-party and “production-ready” applications use the npmprogram to start the application, as shown by the following command:

nohup npm start --production &

The & places the command in the background, and the nohup command ensures that the application continues running even if you log out of the current terminal session.

For this method to work, there must be a valid package.json file for the application. The package.json file contains project metadata that the npm program reads to determine how to start the application, manage its dependencies, and more.

To view the official npm documentation for the package.json file.

Method #2: Run node directly

For simple applications, or for any application that does not have a package.json file, you can run the node executable directly and specify the application filename. For example:

nohup node my_app.js &

However, you lose the benefits of using npm to manage the application.

As above, the & places the command in the background, and the nohupcommand ensures that the application continues running even if you log out of the current terminal session.

STOPPING A NODE.JS APPLICATION

To stop a currently running Node.js application, type the following command:

pkill node

This command immediately stops all running Node.js applications.

INTEGRATING A NODE.JS APPLICATION WITH THE WEB SERVER

Depending on the type of Node.js application you are running, you may want to be able to access it using a web browser. To do this, you need to select an unused port for the Node.js application to listen on, and then define server rewrite rules that redirect visitors to the application. The following steps demonstrate how to do this:

In a text editor, add the following lines to the .htaccess file in the /home/username/public_html directory, where username represents your account username:
```
RewriteEngine On
RewriteRule ^$ http://127.0.0.1:XXXXX/ [P,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ http://127.0.0.1:XXXXX/$1 [P,L]
```
These rewrite rules redirect incoming HTTP visitor requests to the Node.js application running locally on the server. 127.0.0.1 is the loopback address for localhost.
In both RewriteRule lines, replace XXXXX with the port on which your Node.js application listens.
To run a Node.js application on a managed server, you must select an unused port between 49152 and 65535 (inclusive).
Save the changes to the .htaccess file, and then exit the text editor. Visitors to your web site are redirected to the Node.js application listening on the specified port.