This is brief note on how to create a Debian Sarge Xen VM on a Gentoo box. I’m using file-based disk images because it’s so flexible. I don’t believe the partition based ones are actually significantly faster. Inspiration for some of this came from this wiki page.
First I created a 30G LVM volume to hold disk images, created an XFS file system, and mounted it. Then I created a 4GB root image for Debian using XFS as well. I like XFS because it allows me to shrink and expand the filesystem and it also allows me to take snapshots.
hydra xen # lvcreate -L 30G vg1 -n images
Logical volume "images" created
hydra xen # mkdir /etc/xen/images
hydra xen # cat >>/dev/fstab
/dev/vg1/images /etc/xen/images xfs noauto,noatime 0 2
<ctrl-D>
hydra xen # mkfs.xfs /dev/vg1/images
meta-data=/dev/vg1/images isize=256 agcount=16, agsize=491520 blks
= sectsz=512 attr=0
data = bsize=4096 blocks=7864320, imaxpct=25
= sunit=0 swidth=0 blks, unwritten=1
naming =version 2 bsize=4096
log =internal log bsize=4096 blocks=3840, version=1
= sectsz=512 sunit=0 blks
realtime =none extsz=65536 blocks=0, rtextents=0
hydra xen # mount /dev/vg1/images
hydra xen # df -h /dev/vg1/images
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg1-images
30G 13G 18G 41% /etc/xen/images
hydra ~ # dd if=/dev/zero of=/etc/xen/images/debian.root bs=1024k count=4096
4096+0 records in
4096+0 records out
4294967296 bytes (4.3 GB) copied, 129.508 seconds, 33.2 MB/s
hydra xen # mkdir /mnt/xen/debian.root
hydra xen # mkfs.xfs /xen/xen/images/debian.root
meta-data=/big/xen/debian.root isize=256 agcount=8, agsize=131072 blks
= sectsz=512 attr=0
data = bsize=4096 blocks=1048576, imaxpct=25
= sunit=0 swidth=0 blks, unwritten=1
naming =version 2 bsize=4096
log =internal log bsize=4096 blocks=2560, version=1
= sectsz=512 sunit=0 blks
realtime =none extsz=65536 blocks=0, rtextents=0
hydra xen # mount -o loop /etc/xen/images/debian.root /mnt/xen/debian.root
hydra xen #
Now we’re ready to install Debian Sarge:
hydra xen # emerge debootstrap Calculating dependencies ...done! >>> emerge (1 of 2) app-arch/dpkg-1.10.28 to / ... >>> emerge (2 of 2) dev-util/debootstrap-0.2.45-r1 to / ... hydra xen # debootstrap --arch i386 sarge /mnt/xen/debian.root http://ftp.us.debian.org/debian I: Retrieving debootstrap.invalid_dists_sarge_Release I: Validating debootstrap.invalid_dists_sarge_Release I: Retrieving debootstrap.invalid_dists_sarge_main_binary-i386_Packages I: Validating debootstrap.invalid_dists_sarge_main_binary-i386_Packages I: Checking adduser... ... I: Base system installed successfully. umount: /mnt/xen/debian.root/dev/pts: not mounted umount: /mnt/xen/debian.root/dev/shm: not mounted umount: /mnt/xen/debian.root/proc/bus/usb: not mounted hydra xen #
Now we configure the new system:
hydra xen # chroot /mnt/xen/debian.root/ hydra:/# cd /etc hydra:/etc# cat >fstab /dev/sda1 / ext3 defaults 0 1 /dev/sda2 none swap sw 0 0 proc /proc proc defaults 0 0 hydra:/etc# mv /lib/tls /lib/tls.disabled hydra:/etc# exit
Here’s my Xen config file, note that I have a DHCP server with static leases based on the mac address, that’s why I specify it carefully.:
hydra xen # cat debian kernel = "/boot/vmlinuz-2.6.16-r1-xenU" memory = 128 name = "debian" vif = [ 'mac=00:16:3E:00:00:24' ] disk = ['file:/etc/xen/images/debian.root,sda1,w', 'file:/etc/xen/images/debian.swap,sda2,w'] root = "/dev/sda1 ro" hydra xen #
Let’s start the virtual machine!
hydra xen # umount /mnt/xen/debian.root/
