Xen Quick Start

This quick start guide is aim a people who would like to get a virtual machine running with out caring too much about the details. For more detailed information please read the official Xen Documentation

Preparing the Host on SL4

Disable kudzu:

service kudzu stop
chkconfig --del kudzu

Configure NTP and ensure ntpd is running

lcm --configure ntpd
chkconfig ntpd on
service ntpd restart

Disable SELinux

Edit /etc/sysconfig/selinux and ensure SELINUX=disabled

Install yum config for SLC4/i386 dom0/domU:

rpm -ivh http://linuxsoft.cern.ch/cern/xen/slc4X/i386/RPMS/yum-xen-conf-4X-1.slc4.cern.noarch.rpm

Or for x86_64:

rpm -ivh http://linuxsoft.cern.ch/cern/xen/slc4X/x86_64/RPMS/yum-xen-conf-4X-1.slc4.cern.noarch.rpm

Install xen/kernel-xen:

yum install xen kernel-xen

Configure the Xen daemon to start automatically:

chkconfig --add xend
service xend start
chkconfig --add xendomains
service xendomains start

Ensure that check that /boot/grub/grub.conf will boot the Xen kernel by default.

Reboot the system to load the xen kernel

shutdown -r now

Enabling a NAT for the VNs

Edit the configuration file /etc/xen/xend-config.sxp , comment out all the bridge networking settings and add the following

(network-script network-nat)
(vif-script     vif-nat)

Preparing the Guest - tarball method

Create the required partitions

lvcreate --size 10G --name node-01-root vg1
lvcreate --size 500M --name node-01-swap vg1
mkfs.ext3 /dev/vg1/node-01-root
mkswap /dev/vg1/node-01-swap

Create the root filesystem from the tarball

mount /dev/vg1/node-01-root /mnt/
tar zxvf SLC-4-x86.tar.gz -C /mnt/
umount /mnt/

Create the guest configuration file /etc/xen/node-01 - Using NAT

name = "node-01"
memory = 512
disk = [ 'phy:/dev/vg1/node-01-root,xvda1,w','phy:/dev/vg1/node-01-swap,xvda2,w' ]
root = "/dev/xvda1 ro"
vif = [ 'ip=10.0.0.1' ]
bootloader="/usr/bin/pygrub"
on_reboot   = 'restart'
on_crash    = 'restart'
on_poweroff = 'destroy'

Add the IP and hostname to the /etc/hosts on Dom0

10.0.0.1 node-01.cern.ch node-01

Start the VM

xm create node-01

Connect to the VM to set up networking.

xm console node-01
ifconfig eth0 10.0.0.1 up
route add default gw 10.0.0.254

Using Xen

Initialize the guest VM

xm create node-01

List running VMs

xm list

Stop a VM

xm destroy node-01

To exit from the console

ctr-]

-- LaurenceField - 23 Jun 2008