EPEL (Extra Packages for Enterprise Linux) 有提供一些額外套件(CentOS-* Base/Extras/Updates以外的)
# for RHEL/CentOS 7 64-Bit
yum -y install epel-release
or
rpm -ivh http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
# for RHEL/CentOS 6 64-Bit
rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# for RHEL/CentOS 5 64-Bit
rpm -ivh http://download.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
# list EPEL packages
yum --disablerepo="*" --enablerepo="epel" list available
ref. How to Enable EPEL Repository for RHEL/CentOS 7.x/6.x/5.x