This article describes how to configure a CentOS or Red Hat Enterprise Linux system to use the Fedora Extra Packages for Enterprise Linux (EPEL) repository. The EPEL repository provides useful software packages that are not included in the official CentOS or Red Hat repositories.

Instructions are also included for installing the IUS Community Project. Whereas EPEL provides only software that is not in the official CentOS and Red Hat repositories, IUS provides newer versions of software (like MySQL and PHP) that exist in the official repositories.

Note: Exercise caution when using any third-party repository. If you have a managed support agreement, contact your provider before following the instructions in this article to ensure that you don’t create an unsupported server configuration.

Install the EPEL repository

You install the EPEL repository by downloading the appropriate RPM package for your system and installing it. The following instructions use the 64-bit packages that work with Rackspace Cloud Servers instances.

CentOS

The CentOS Extras repository includes a package to install EPEL, and is enabled by default. To install the EPEL release package, run the following command:

sudo yum install epel-release

Red Hat Enterprise Linux

To install the EPEL release package, run the following command:

sudo yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-$(rpm -E '%{rhel}').noarch.rpm

Some EPEL packages depend on packages from the “optional” and “extras” channels, so ensure that those are enabled as well.

Install the IUS repository

The IUS repository provides newer versions of some software in the official CentOS and Red Hat repositories. The IUS repository depends on the EPEL repository.

The package names in the IUS repository are different from the package names used in the official repositories. The difference helps to avoid unintentional conflicts or software version updates.

Note: Because IUS uses package names that are different from the package names in the official repositories, we recommend IUS for Rackspace customers with managed support levels that include server software. Managed servers automatically update nightly by default, which can cause unplanned upgrades if package names are the same in more than one enabled repository.

To install the IUS release package, run the following command:

sudo yum install https://repo.ius.io/ius-release-el$(rpm -E '%{rhel}').rpm

Upgrade installed packages to IUS versions

If you already have a software package installed that you want to upgrade to a newer version in the IUS repository, install the IUS yum plug-in for package replacement to simplify the upgrade process.

sudo yum install yum-plugin-replace

The plug-in provides a yum replace command that replaces a specified package and installs any required dependencies at the same time. For example, to replace the installed PHP package with the PHP 5.6 package from the IUS repository, run the following command:

sudo yum replace php --replace-with php56u

For more information, see the IUS Usage Guide.

Check for available repositories

You can see if the repositories that you need are installed and enabled by running the following command:

yum repolist

Some repositories are disabled by default. To list disabled repositories, run the following command:

yum repolist disabled