epel-7-x86_64

Create a new Channel:

Fill the fields!

Channel Name:

epel-7-x86_64

Channel Label:

epel-7-x86_64

Parent Channel:

CentOS 7 Base x86_64

Architecture:

x86_64

Channel Summary:

epel-7-x86_64

Scroll down the page and enter:
GPG key URL:

https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7

GPG key ID:

352C64E5

GPG key Fingerprint:

91E9 7D7C 4A5E 96F1 7F3E  888F 6A2F AEA2 352C 64E5

Open [Channels] section, go for [Manage Software Channels],
go for [Manage Repositories], click [Create Repository]

Fill down:
Repository Label:

epel-7-x86_64

Repository URL:

https://dl.fedoraproject.org/pub/epel/7/x86_64/

Click [Create Repository]

Now open your child channel:

Assign child repository to child channel and press [Update Repositories] button:

Now at the command line execute:

spacewalk-repo-sync -c epel-7-x86_64

Appendix:

curl "http://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-7" > /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
cp /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7 /var/www/html/pub/RPM-GPG-KEY-EPEL-7
gpg --with-fingerprint /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7