This is an extremly brief and quick Xen tutorial. There are lots of them already, see your GNU/Linux distribution’s wiki, HowtoForge or other places for a starter guide. This particular HowTo deals with setting up Xen as easy as possible using Ubuntu 8.04 LTS as host operating system (dom0 in Xen terms) and Ubuntu 9.04 as guest operating systems (domU in Xen lingo).
Ubuntu 8.04 LTS comes with a Xen kernel that can run as dom0. This is quite important, so pay attention to setting that up correctly. For this I recommend the HowtoForge Tutorial.
Note: you will need to upgrade the default Xen 3.2 to 3.3 to be able
to run the latest distributions as guest OS. See this
Ubuntu question for more insight. To get Xen 3.3, simply activate
the Hardy backports repository in your
/etc/apt/sources.list and, as
usual, pay attention to your
/boot/grub/menu.lst so that it points out
the Xen 3.3 image in the
When done with the basic setup you should install pygrub on your host, this is a truly magic piece of software that makes it possible to boot all guests using their own kernel and modules. See the Debian wiki for some details on install and setup. Then ignore what you read and do like this:
# /var/lib/xend/domains/example/config.sxp - Xen domU example. # Note the order of partitions in disk=, the first listed partition # is the partition where your /boot (grub) resides. bootloader = '/usr/bin/pygrub' builder = 'linux' memory = '2048' root = '/dev/xvda1 ro' disk = [ 'phy:/dev/disk/by-uuid/df3418f5-2fc3-443c-8e64-4395828dc678,xvda1,w', 'phy:/dev/disk/by-uuid/acecf01e-c4d9-4a7b-b18a-681c69f71173,xvda2,w', ] name = 'example' vif = [ 'bridge=eth1' ] dhcp = "off" ip = "22.214.171.124" netmask = "255.255.255.252" gateway = "126.96.36.199" hostname = "example" on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' vcpus = 1 extra = 'xencons=tty1'
When installing grub on your guest, don’t pay any attention to Grub
complaining about not being able to map
/dev/xvda1 to a BIOS disk.
pyGrub doesn’t care about such wordly things as physical disks. Just
make sure the
/boot directory’s partition (often
/) is the first
listed in the
disk= array above.
You may need to edit the
update-grub script before you install grub,
it is located at
/usr/sbin/update-grub. Search for
in_xen, a fairly
long way down. Make sure it’s set to
in_xen=1 before the big
if-clause that depends on it. Without this fix the Xen able kernels
in Ubuntu 9.04, and later, are not detected.
update-grub and answer yes to the questions. Take good care to
verify that the script actually finds one active (server) kernel and
adds it properly to your
Another common problem is the lack of a console login. Usually you
don’t need one, but if you’d like to check your domU from within your
dom0 you need to add the file “console” to
# console - getty # # This service maintains a getty on the Xen serial console # from the point the system is started until it is shut # down again. start on stopped rc2 start on stopped rc3 start on stopped rc4 start on stopped rc5 stop on runlevel 0 stop on runlevel 1 stop on runlevel 6 respawn exec /sbin/getty 38400 console
That should do the trick! If it doesn’t, then there’s plenty of help to find in the Debian and Ubuntu wikis, see links above. Good luck!