Configuring a Third Party Repository
There are two ways to configure a third-part repository, either manually or through yum-config-manager
1) Yum-config-manager option
a) Yum-config-manager –add-repo=ADDREPO [add (and enable) the repo from the specified file or url]
yum-config-manager --add-repo=http://dl.fedoraproject.org/pub/epel/7/x86_64/
b) The yum configured third party repository will be configured in /etc/yum.repos.d file
c) It is generally important to download the GPG key; so do cd /etc/pki/rpm-gpg;
wget https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7
d) Then you would edit the /etc/yum.repos.d/fedoraproject.repo and edit the last two lines, the yum-config-manager adds the rest of the lines manually
[dl.fedoraproject.org_pub_epel_7_x86_64_]
name=added from: http://dl.fedoraproject.org/pub/epel/7/x86_64/
baseurl=http://dl.fedoraproject.org/pub/epel/7/x86_64/
enabled=1
[the below two lines you would need to add to the configuration after yum-config-manager command
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
2) Manually configuring the repo configuration
a) You would download the gpgkey from step 1 c) and then you would create the entire file in step (1-d) from scratch without any commands
3) Please note that you can disable a repo with the command yum-config-manager –disable [name of repo] but you can only remove a repo from the server by removing the file located in /etc/yum/repos.d