25 Oct 09 Move Xen Guest from loopback filesystem to LVM

Moving a Xen Guest into an LVM container from a loopback sparse image is easy enough.

You’ll need to power down the VM using xm shutdown mymachine

Once done, create the logical volume with: lvcreate –name mymachine-disk –size 10G myvg 10G should match the exact size (if not more) of your current VM. Now create the same for the swap file: lvcreate -name mymachine-swap -size 128M myvg. Now edit your machine’s config (/etc/xen/mymachine.cfg), replacing the disk part from:

disk        = [
'file:/xen/mymachine/mymachine-swap,sda1,w',
'file:/xen/mymachine/mymachine-disk,sda2,w',
]

to

disk        = [
'phy:/dev/myvg/mymachine-swap,sda1,w',
'phy:/dev/myvg/mymachine-disk,sda2,w',
]

And use dd to write the disk to your new LVM filesystem:

dd if=/xen/mymachine/mymachine-disk of=/dev/myvg/mymachine-disk
dd if=/xen/mymachine/mymachine-swap of=/dev/myvg/mymachine-swap

Remembering that you can use killall -SIGUSR1 dd at any time to gain a status update on dd’s IO.

Once done, power up your VM again with xm create mymachine.cfg

Tags: dd, disk, dom0, domu, killall, lvm, xen, xm

18 Oct 09 Installing and Configuring Xen with guests

Installing and Configuring Xen on a Debian Lenny machine is pretty easy. Firstly, install the system:

apt-get install xen-tools xen-utils-3.2-1 xen-linux-system-2.6.26-2-xen-686

xen-linux-system-2.6.26-2-xen-686 comes with the Xen kernel that you’ll need. It should install a new kernel as the default, and therefore you’ll now need to reboot.

Once rebooted, issue uname -a to ensure that your new Xen kernel is running:

You now have Xen installed! Now, you’ll need to make a few changes. Firstly, none of my new guest VMs had working console, apparently this is a known issue in Lenny with Lenny guests. The work around is to change the inittab on the guest. I wanted to create guests without modifications, so in this case, I edited /etc/xen-tools/xen-tools.conf and uncommented:

#serial_device = hvc0 #default

It’s listed as the default, but uncommenting this seemed to solve my issues.

Now, you’re ready to create your first guest:
(more…)

Tags: apt-get, debian, lenny, Linux, uname, xen, xm