How to Build a Yum Repository [Updated]

yum install yum-utils createrepo vsftpd

Create the directory: /var/ftp/pub/yum/*OSName*/*RELEASE*/*PATCH*/base/*ARCH*

examples:

/var/ftp/pub/yum/centos/6/6/base/i386
/var/ftp/pub/yum/centos/6/6/base/x86_64
/var/ftp/pub/yum/RHEL/7/1/base/x86_64

mkdir -p /var/ftp/pub/yum/centos/6/6/base/x86_64

Option 1:  From Install CD

Required:  Installation Media

cp -ar /*CDMOUNTPOINT*/Packages/* /var/ftp/pub/yum/centos/6/6/base/x86_64
cp /*CDMOUNTPOINT*/repodata/*comps*.xml /opt/yum/rhel6.3/repodata/comps.xml

Option 2:  From an Internet Repo

Required:  Internet Connection

If you do it this way, you are grabbing the latest patches from a repository on the internet.

reposync --gpgcheck -l -p /etc/yum.repos.d/redhat-rhui.repo --download_path=/var/ftp/pub/yum/RHEL/7/1/base/x86_64 --downloadcomps --download-metadata

Source:  Link Link Link 

Server Config

service vsftpd start

*If running iptables, you will have to allow it through the firewall

cd /var/ftp/pub/yum/centos/6/6/base/x86_64
createrepo -v .

vim /etc/yum.reposb.d/custom.repo

[name]
name=Centos $releasever Base Updates 6.6
baseurl=ftp://*ip-of-the-computer*/pub/centos/6/6/base/x86_64 enable=1 gpgcheck=0 (this can be changed to 1 once the certs are installed on the system)

yum clean all
yum repolist

Your repo should now be listed

Couple of Notes:
SELinux and the firewall was turned off while doing this

Note:  Some systems may require you to run yum-arch /var/ftp/pub/yum/centos

Tested In: CentOS 4.3, 6.6, RHEL 6.4 (just change version numbers above to match your version of the OS)

Troubleshooting:

repomd.xml: [Errno 14] PYCURL ERROR 9 - "Server denied you to change to the given directory" Trying other mirror."