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Background to 32bit Xen

This is on a server with 8GB of RAM. It had a bigmem kernel installed to begin with. The default 32bit Xen kernel that comes with Debian has PAE enabled, allowing all of the 8GB of RAM to be seen by Xen. Below is the output of free and uname -a.


Debian-50-lenny-32-minimal:~# free

            total       used       free     shared    buffers     cached

Mem: 8301232 179796 8121436 0 41128 103980 Debian-50-lenny-32-minimal:~# uname -a Linux Debian-50-lenny-32-minimal 2.6.26-2-686-bigmem #1 SMP Thu Sep 16 20:29:07 UTC 2010 i686 GNU/Linux

Installation and Reboot

apt-get install xen-hypervisor-3.2-1-i386 linux-image-2.6-xen-686 # vi /boot/grub/menu.lst. Check default and entries. # reboot That's actually all there is involved. Debian's dependancies will select and install all additional packages required.


Debian-50-lenny-32-minimal:~# free

            total       used       free     shared    buffers     cached

Mem: 8171204 212232 7958972 0 2492 20096 Debian-50-lenny-32-minimal:~# uname -a Linux Debian-50-lenny-32-minimal 2.6.26-2-xen-686 #1 SMP Fri Sep 17 00:54:08 UTC 2010 i686 GNU/Linux Debian-50-lenny-32-minimal:~# xm list Name ID Mem VCPUs State Time(s) Domain-0 0 7979 8 r—– 8.5

All 8GB memory is available for use. (By default xen3.2 uses PAE).

Tweaks to dom0

These tweaks will help make dom0 more stable. It fixes the amount of memory available instead of having to balloon out. The networking is set to network-bridge as this is the most basic and easiest setup. vi /boot/grub/menu.lst //Change # xenhopt= //TO: # xenhopt=dom0_mem=256000 :wq

update-grub # ^ This will recreate the menu.lst. Check and go “vi menu.lst”, it should now read: kernel /xen-3.2-1-i386.gz dom0_mem=256000)

vi /etc/xen/xend-config.sxp //change (dom0-min-mem 196) to: (dom0-min-mem 256) //change (network-script network-dummy) to: (network-script network-bridge)

Create DomU

In this example a file based disk image will be used. It's possible to use LVM. For a LVM DomU creation see LVM_on_XEN_(dom0) mkdir -p /xens/vm01 dd if=/dev/zero of=/xens/vm01/disk-vm01.img bs=1024k count=5000 dd if=/dev/zero of=/xens/vm01/swap-vm01.img bs=1024k count=512 mkfs.ext3 /xens/vm01/disk-vm01.img (press y to continue if asked) mkswap /xens/vm01/swap-vm01.img mount -o loop /xens/vm01/disk-vm01.img /mnt/ apt-get install debootstrap debootstrap lenny /mnt cp /etc/apt/sources.list /mnt/etc/apt/ cp /etc/resolv.conf /mnt/etc/ cp /etc/network/interfaces /mnt/etc/network/ vi /mnt/etc/network/interfaces (update as necessary) vi /mnt/etc/hostname vi /mnt/etc/fstab # UNCONFIGURED FSTAB FOR BASE SYSTEM proc /proc proc defaults 0 0 /dev/sda1 / ext3 defaults,errors=remount-ro 0 1 /dev/sda2 none swap sw 0 0

chroot /mnt/ apt-get install udev exit (from udev)

vi /etc/xens/vm01 kernel = “/boot/vmlinuz-2.6.26-2-xen-686” ramdisk = “/boot/initrd.img-2.6.26-2-xen-686” memory = 512 name = “vm01” vif = 'bridge=xenbr0' disk = /xens/vm01/swap-vm01.img,sda2,w' ip = “” gateway = “” netmask = “” root = “/dev/sda1 ro” extra = 'xencons=tty clocksource=jiffies'

ln -s /etc/xen/vm01 /etc/xen/auto/vm01 //link in the config file so that the Virtal Machine starts on Bootup of Dom0

Start DomU

cd /etc/xen xm create -c vm01 //Login with root. There will be no password set. passwd to change the password. apt-get install linux-modules-2.6-xen-686 iptables -L (to test) //To exit the Xen Console: CTRL + ]


So this will setup a basic Xen system with bridged networking and a file based disk image. All of the above was done on a basic installation of Debian Lenny. If you are new to Xen, I highly recommend you read over: Archive

basic_setup_of_xen3.2_32bit.txt · Last modified: 2022/07/19 21:13 by