The following instruction assumes that you are running command as root user on a CentOS/RHEL 7.x system and you would like to use Fedora Epel repositories.
Install Extra Packages for Enterprise Linux repository configuration (recommended). Just type the following command on a CentOS 7 or RHEL 7:
root# yum install epel-release
Install the extra EPEL repositories from dl.fedoraproject.org :
root# cd /tmp
root# wget https://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
root# ls *.rpm
root# rpm -i epel-release-7-5.noarch.rpm