centos-6-extras-x86_64

Create a new Channel:

Fill the fields!

Channel Name:

centos-6-extras-x86_64

Channel Label:

centos-6-extras-x86_64

Parent Channel:

CentOS 6 Base x86_64

Architecture:

x86_64

Channel Summary:

centos-6-extras-x86_64

Scroll down the page and enter:
GPG key URL:

http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6

GPG key ID:

C105B9DE

GPG key Fingerprint:

C1DA C52D 1664 E8A4 386D  BA43 0946 FCA2 C105 B9DE

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

Fill down:
Repository Label:

centos-6-extras-x86_64

Repository URL:

http://centos.koyanet.lv/centos/6/extras/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 centos-6-extras-x86_64

Install channel key locally:

curl "http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-6" > /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
cp /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 /var/www/html/pub/RPM-GPG-KEY-CentOS-6
gpg --with-fingerprint /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6