EPEL Yum Repository in CentOS

As Ansible, an automation tool, is not included to the default Yum repository in CentOS 6, you've to setup Extra Packages for Enterprise Linux (EPEL) Yum repository. I found this article on setting up EPEL repository and realize that I've been doing it the wrong way all this while. Instead of downloading the EPEL rpm package separately, we can install it directly as it's already located within the CentOS Extra Repository just by running the command below.

$ sudo yum install epel-release

Extra information on the epel-release package.

$ yum show epel-release
......
Installed Packages
Name        : epel-release
Arch        : noarch
Version     : 6
Release     : 8
Size        : 22 k
Repo        : installed
From repo   : extras
Summary     : Extra Packages for Enterprise Linux repository configuration
URL         : http://dl.fedoraproject.org/pub/epel/
License     : GPLv2
Description : This package contains the Extra Packages for Enterprise Linux (EPEL) repository
: GPG key as well as configuration for yum and up2date.

Listing the files within the epel-release package.

$ rpm -ql epel-release
/etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
/etc/rpm/macros.ghc-srpm
/etc/yum.repos.d/epel-testing.repo
/etc/yum.repos.d/epel.repo
/usr/share/doc/epel-release-6
/usr/share/doc/epel-release-6/GPL

Getting the list of RPM packages from EPEL repository.
$ yum list | grep epel

Since this is third-party YUM repository, certain system administrator may prefer to disable it by default and only install certain package from it when necessary.

$ cat /etc/yum.repos.d/epel* | grep enabled
enabled=0
enabled=0
enabled=0
enabled=1
enabled=0
enabled=0
$ sed -i 's/enabled=1/enabled=0/g' /etc/yum.repos.d/epel*
$ cat /etc/yum.repos.d/epel* | grep enabled
enabled=0
enabled=0
enabled=0
enabled=0
enabled=0
enabled=0

If you've installed any packages from this Yum repository. You should clear all the downloaded cache RPM packages..

$ yum clean all

Unfortunately, to perform any yum commands against this repository, we've to explicitly state the repository for every command. Some examples.

$ yum search --enablerepo=epel ansible
$ yum list --enablerepo=epel | grep epel | grep ansible
$ yum install --enablerepo=epel ansible

Indeed a bit hassle to type all these commands. You can create an alias to reduce the needless typing.

$ alias yumepel="yum --enablerepo='epel'"
$ yumepel search ansible