[gentoo-user] Facilities for creating Gentoo Linux based virtual appliances

[Albert Hopkins]

Hello,

For a while I have been assembling methods for myself to be able to
easily create Gentoo-based virtual appliances.  I have worked with
Ubuntu's vmbuilder scripts and basically wanted the same or similar ease
of use with Linux.

To make a long story short, I threw together a Makefile which basically
gives me this ability.  I have it at a state where it's pretty much
useful to me for my purposes.  But I thought someone else may find use
for it as well, so I put it up on Bitbucket:

https://bitbucket.org/marduk/virtual-appliance

The Makefile pretty much does an install into a chroot, pretty much by
the handbook, with a few alterations where I saw fit.  It hast some
variables and a couple of hooks to allow for customization.  I've
already created a few appliances (included) such as:

base: A base install of Gentoo Linux
gnome: GNOME stable appliance (no GUI console)
kde: KDE stable appliance (no GUI console)
lodgeit: Lodgeit pastebin appliance[1]
teamplayer: TeamPlayer appliance

The "no GUI console" means that by default these appliances don't have
an X console.  I usually log into them via XDMCP or ssh.  So they can be
thought of as "headless" desktop virtual appliances.  The "base"
appliance is pretty much the handbook, with dhcpd and a syslog and
nothing else.  TeamPlayer is a "democratic Internet radio station" web
app that I have been developing.  To date I have not distributed it,
though eventually plan to.  You can contact me directly if interested.

Right now there is no documentation or copyright or anything.  It's
pretty much just the code.  Like I said this has been primarily for my
personal use so there is nothing fancy like packaging or anything, but
it works.  Some things can probably be done better.  I'm no expert at
writing Makefiles.

So the way you basically use it is like this:

$ sudo make APPLIANCE=gnome VIRTIO=YES qcow

This will create a gnome virtual appliance image configured for virtio
and supply a qcow (qcow2) disk image.  You can also just "sudo make" for
which the default is to create a "base" appliance not configured with
VIRTIO and only supply an image file in raw format.  There are other
make variables that can be supplied.  Check out the Makefile.

You can "easily" create your own VM appliaces by just mkdir
<appliance-name>.  Copy the files from base/* into it and edit them as
needed.  The supplied appliances should be good references.

One warning: the Makefile must be run as root, and does things inside a
chroot.  I have been careful to make sure everything is done in the
chroot that needs to be.  It is possible for you (or me) to forget to
put chroot before a command and cause irreversible damage to your host
system.  Just giving you this caveat.    I'm sure the appliances I
provided are safe, but I can't guarantee it and if you make your own
appliance just be careful.  Ideally one would build VM appliances inside
a VM appliance itself :)

Well, I probably left some stuff out.  Feel free to reply (to this
thread I guess) if you have any questions.

Oh, when you are finished building your disk image just

$ sudo make clean

Which will unmount things and remove the temporary files.  

A FEW MORE IMPORTANT THINGS: 
In the Makefile, I have PORTAGE=/portage and
DISTFILES=/var/portage/distfiles.  These are my setup and are not the
defaults.  You will need to change these values appropriately.   Also,
you may need to edit the USEPKG variable.  I have the Makefile use my
binary packages to speed up the creation process (allows me to build a
base appliance in about 12 minutes).  You may not want this, especially
if you have your CFLAGS tuned to a specific processor that your
hypervisor does not support.  But I use generic CFLAGS so I have no
problem using binpkgs.

Oh, I use kvm/virt-manager and use virtio for disks and network devices.
I tried to configure the VM kernel so that it will support other
formats.  I am curious as to whether or not the appliances will work
with VMWare as I have not actually tried it, but you should be able to
create a VM image with

$ sudo make vmdk

I'm probably leaving something out.  You should take a look at the
Makefile first if you are going to use it.  It shouldn't be that foreign
(it's basically handbook stuff but tailored for the use case).

Anyway it's out there for you to reference.

-a

[1] http://dev.pocoo.org/projects/lodgeit/