Introduction and Prerequisites
Note: This tutorial is for those still using RHEL 7/RHEL 6 and need to install a version Node.js. If you are using a more recent version of RHEL, please see this article
In this tutorial, you will set your system up to install software from Red Hat Software Collections (RHSCL), which provides the latest development technologies for Red Hat Enterprise Linux. Then, you will install Node.js v8 and run a simple “Hello, World” application. The whole tutorial should take less than 10 minutes to complete.
Before you begin, you will need a current Red Hat Enterprise Linux 7 (or RHEL 6) server or workstation subscription that allows you to download software and get updates from Red Hat. Developers can get a no-cost Red Hat Enterprise Linux Developer Suite subscription for development purposes by registering and downloading through developers.redhat.com.
If you need help, see Troubleshooting and FAQ.
1. Enable Node.js Red Hat Software Collection
2 minutes
In this step you will configure your system to obtain software, including the latest dynamic languages, from the RHSCL software repository. Instructions are provided for both the command line (CLI) and graphical user interface (GUI).
Note for RHEL 6 users: If your system uses Red Hat Network (RHN) Classic instead of Red Hat Subscription Management (RHSM) for managing subscriptions and entitlements, please skip this step and follow the Installation chapter of the Red Hat Software Collections Release Notes. The instructions in this section are only for systems using RHSM. The remainder of this tutorial applies to systems running either RHSM or RHN Classic.
Using the Red Hat Subscription Manager GUI
Start Red Hat Subscription Manager using the System Tools group of the Applications menu. Alternatively, you can start it from the command prompt by typing subscription-manager-gui.
- Select Repositories from the System menu of the subscription manager.
- In the list of repositories, check the Enabled column for rhel-server-rhscl-7-rpms and rhel-7-server-optional-rpms (or rhel-server-rhscl-6-rpms and rhel-6-server-optional-rpms). If you are using a workstation version of Red Hat Enterprise Linux, the repositories will be named rhel-workstation-rhscl-7-rpms and rhel-7-workstation-optional-rpms (or rhel-desktop-rhscl-6-rpms and rhel-6-desktop-optional-rpms). Note: After clicking, it might take several seconds for the check mark to appear in the enabled column.
If you don’t see any RHSCL repositories in the list, your subscription might not include it. See Troubleshooting and FAQ for more information.
Using subscription-manager from the command line
You can add or remove software repositories from the command line using the subscription-manager tool as the root user. Use the --list option to view the available software repositories and verify that you have access to RHSCL:
$ su -
# subscription-manager repos --list | egrep rhscl
If you don’t see any RHSCL repositories in the list, your subscription might not include it. See Troubleshooting and FAQ for more information.
If you are using a workstation edition of Red Hat Enterprise Linux, change -server- to -workstation- in the following commands:
# subscription-manager repos --enable rhel-server-rhscl-7-rpms
# subscription-manager repos --enable rhel-7-server-optional-rpms
or for RHEL 6:
# subscription-manager repos --enable rhel-server-rhscl-6-rpms
# subscription-manager repos --enable rhel-6-server-optional-rpms
2. Setup your Node.js development environment
2 minutes
Next step, install Node.js v4 from RHSCL:
$ su -
# yum install rh-nodejs8
Note: In Node.js v8, the JavaScript v8 runtime is built in. A separate package is no longer required.
3. Hello World and your first Node.js application
2 minutes
Under your normal user ID, start a Terminal window. First, use scl enable to add Node.js v4 to your environment, then run Node.js to check the version.
$ scl enable rh-nodejs8 bash
$ node --version
v8.6.0
The next step is to create a Node.js program that can be run from the command line. Using a text editor such as vi, nano, or geditcreate a file named hello.js with the following content:
console.log("Hello, Red Hat Developer Program World from Node " + process.version)
Save it and exit the editor. Run it with the node command:
$ node ./hello.js
Hello, Red Hat Developer Program World from Node v8.6.0
If you get the error: node command not found, you need to run scl enable rh-nodejs8 bash first.
The next step is to try a slightly larger Node.js example that implements a tiny web server. Using your preferred text editor, create a file named hello-http.js with the following content:
var http = require('http');
var port = 8000;
var laddr = '0.0.0.0';
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello, Red Hat Developer Program World from ' +
process.version + '!\n');
console.log('Processed request for '+ req.url);
}).listen(port, laddr);
console.log('Server running at http://' + laddr + ':' + port + '/');
Save it and exit the editor. Run it with the node command:
$ node ./hello-http.js
Now use curl, or a browser such as Firefox, to connect to the Node.js web server http://localhost:8000/:
$ curl http://localhost:8000/
Hello, Red Hat Developer Program World from v8.6.0!
Working with RHSCL packages
The software packages in RHSCL are designed to allow multiple versions of software to be installed concurrently. To accomplish this, the desired package is added to your runtime environment as needed with the scl enable command. When scl enable runs, it modifies environment variables and then runs the specified command. The environmental changes only affect the command that is run by scl and any processes that are run from that command. The steps in this tutorial run the command bash to start a new interactive shell to work in the updated environment. The changes aren’t permanent. Typing exit will return to the original shell with the original environment. Each time you login, or start a new terminal session, scl enable needs to be run again.
While it is possible to change the system profile to make RHSCL packages part of the system’s global environment, this is not recommended. Doing this can cause conflicts and unexpected problems with other applications because the system version of the package is obscured by having the RHSCL version in the path first.
Permanently enable RHSCL in your development environment
To make one or more RHSCL packages a permanent part of your development environment, you can add it to the login script for your specific user ID. this is the recommend approach for development as only processes run under your user ID will be affected.
Using your preferred text editor, add the following line to your ~/.bashrc:
# Add Node.js v8 from RHSCL to my login environment
source scl_source enable rh-nodejs8
After making the change, you should log out and log back in again.
When you deliver an application that uses RHSCL packages, a best practice is to have your startup script handle the scl enable step for your application. You should not ask your users to change their environment as this is likely to create conflicts with other applications.
Where to go next?
If you want to learn more about what Red Hat is up to on the Node.js front, check out our Node.js page here.
View documentation on the Nodejs.org web site
http://nodejs.org/documentation/
Find additional Node.js packages in RHSCL
$ yum list available rh-nodejs4-\*
View the full list of packages available in RHSCL
$ yum --disablerepo="*" --enablerepo="rhel-server-rhscl-7-rpms" list available
or for RHEL 6:
$ yum --disablerepo="*" --enablerepo="rhel-server-rhscl-6-rpms" list available
Want to know more about Software Collections?
- Read the Red Hat Software Collections Release Notes and Packaging Guide
Developers should read the packaging guide to get a more complete understanding of how software collections work, and how to deliver software that uses RHSCL. Become a Red Hat developer: developers.redhat.com Red Hat delivers the resources and ecosystem of experts to help you be more productive and build great solutions. Register for free at developers.redhat.com.
