If you currently do not hold a Red Hat Subscription and yet you need to enable EPEL ( Extra Packages for Enterprise Linux ) repository on your RHEL 7 Linux you need to download and install following file directly from Fedora project:
epel-release-7-5.noarch.rpm
Please note the version the version name may change so consult fedora projec URL’s http://dl.fedoraproject.org/pub/epel/7/x86_64/e/ to get a current package name. First download your file making sure that you have a correct package name:
$ wget http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
Once downloaded install package using a following linux command:
# rpm -Uvh epel-release*.rpm
Once the the above package is installed epel repository should appear on your list:
# yum repolist | grep epel epel/x86_64 Extra Packages for Enterprise Linux 7 - x86_64 7,534