Description of problem:

Virt-builder is a tool for quickly customizing cloud images
of various operating systems.  For example you can do:

  virt-builder fedora-19 --format qcow2 --size 20G --install @XFCE

and get a custom Fedora 19 image with plenty of disk space and
XFCE desktop installed.

If everything is cached, the process takes between 30 seconds and
a couple of minutes.

Note this is different from Oz (it doesn't do a full install)
and different from livecd-tools (it doesn't make installers).
It is more similar to doing virt-resize + virt-sysprep.

Virt-builder is a new feature which was added in libguestfs 1.24.
Adding it to RHEL 7.1 (rebase: bug 1021149) is trivial.

However if we were just to add it, then it would offer a less-than-ideal
choice of images to install:

  $ virt-builder -l
  centos-6                 CentOS 6.4
  debian-6                 Debian 6 (Squeeze)
  debian-7                 Debian 7 (Wheezy)
  fedora-18                Fedora® 18
  fedora-19                Fedora® 19
  scientificlinux-6        Scientific Linux 6.4
  ubuntu-10.04             Ubuntu 10.04 (Lucid)
  ubuntu-12.04             Ubuntu 12.04 (Precise)
  ubuntu-13.10             Ubuntu 13.10 (Saucy)

So the real issue is not how to add it, but how and where to
host RHEL cloud images, and possibly how to make sure these
cloud images attach automatically to RHN for updates etc.

Version-Release number of selected component (if applicable):

libguestfs 1.24
libguestfs 1.25 contains several new features which are
candidates for backporting.

Additional info:

A thread explaining how to try out virt-builder now:
http://post-office.corp.redhat.com/archives/rhos-tech/2013-November/msg00086.html

It's possible we could use this in RHOS instead of the fundamentally
insecure disk-image-builder tool.  See the thread starting here:
http://post-office.corp.redhat.com/archives/rhos-tech/2013-November/thread.html#00097

I have built a collection of RHEL cloud images internally.
To use them, do:
export VIRT_BUILDER_SOURCE=http://file.rdu.redhat.com/~rjones/builder/index.asc
and then run virt-builder as normal, eg:

$ virt-builder -l
rhel-6.1                 Red Hat Enterprise Linux 6.1
rhel-6.2                 Red Hat Enterprise Linux 6.2
rhel-6.3                 Red Hat Enterprise Linux 6.3
rhel-6.4                 Red Hat Enterprise Linux 6.4

Note that these don't use RHN.  Their yum configuration
points directly at http://download.devel.redhat.com/released/
Adding RHN support to virt-builder is TBD.