How to: Install and Setup XEN Virtualization Software on CentOS Linux 5

by Vivek Gite · 13 comments

One of our regular reader asks:

I'm using CentOS Linux 5 server. How do I set up Xen on Linux ? How do I install guest VPS oses such as Fedora or Windows 2000 or Debian Linux inside XEN?

Xen is a free open source software virtual machine monitor for Intel / PowerPC architectures. It is software that runs on a host operating system and allows several guest operating systems to be run on top of the host on the same computer hardware at the same time (just like VMWare software). Luckily Installing and managing XEN is quite easy under CentOS 5 Linux.

Login as the root and type the following commands:
# yum install xen virt-manager kernel-xen # chkconfig xend on # reboot

Make sure you boot CentOS server using XEN kernel.

How do I install NetBSD / any Linux distro / Windows 2000 inside XEN?

Simply use gui tool called virt-manager:
# virt-manager &

Now just follow on screen instructions to setup new guest operating systems (VPS oses). virt-manager is Xen Management Consoles software. It can perform the common tasks of administering a Xen host such as configuring, starting, monitoring and stopping of Xen guests oses. Please note that above instructions also works on

RHEL 5
Fedora Linux 7

Installing CentOS 5.3 guest using the Internet

virt-install is a command line tool for provisioning new virtual machines using the "libvirt" hypervisor management library. Type the following command to install CentOS v5.3 64 bit as guest operating system in /vm:
# mkdir /vm
If you are using SELinux, enter:
# semanage fcontext -a -t xen_image_t "/vm(/.*)?" # restorecon -R /vm # ls -dZ /vm
Above will provide security context of Xen images. Finally, install CentOS 5.3 using the Internet mirror:
# virt-install \ --paravirt \ --name webserver01 \ --ram 512 \ --file /vm/webserver.nixcraft.com.img \ --file-size 10 \ --nographics \ --location http://mirrors.kernel.org/centos/5.3/os/x86_64/
Above will CentOS as a paravirtualized Xen guest, with 512 MB of RAM, a 10 GB of disk, and from a web server, in text-only mode. You need to just follow on screen instructions.

(CentOS XEN Guest Installation in a text mode over ssh session)

Once installed you can use xm command to list, start, stop and manage xen vps:
# xen list
Attach console to domain / guest called webserver01:
# xm console webserver01
See xm command cheat sheet.

Installing CentOS 5.3 guest using DVD

Install a CentOS guest, using LVM partition, virtual networking, booting from the host CDROM, using VNC server/viewer (insert DVD into drive):
# virt-install \ --connect qemu:///system \ --name mailserver --ram 500 \ --file /dev/HostVG/mailserver.cyberciti.biz \ --network network:default \ --accelerate \ --vnc \ --cdrom /dev/cdrom
Note you need qemu and virt-viewer installed on the host system.

Installing Fedora guest using DVD iso image stored on hard disk

Install a Fedora Linux, with a real partition (/dev/sdc), using a local DVD ISO image:
# virt-install \ --name www2 \ --ram 1000 \ --file /dev/sdc \ --network bridge:eth1 \ --cdrom /tmp/fedorabootdvd.iso

Further readings:

man page virt-install and xm
XEN project
Virtual Machine Manager project
Enomalism project
ConVirt project

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{ 13 comments… read them below or add one }

1 Artem Nosulchik 10.18.07 at 8:14 pm: Nice one! Is it necessary to enable any additional yum repositories in CentOS 5 in order to install xen, virt-manager and kernel-xen packages?
2 vivek 10.18.07 at 8:38 pm: Noop, you can install from DVD or just download and install using yum.
3 raj 10.23.07 at 1:27 pm: Really easy, thanks for all info :)
4 Scott 01.09.08 at 8:38 pm: “Now just follow on screen instructions to setup new guest operating systems (VPS oses). ”

You’re kidding, right? How unfortunate this topic got indexed in Google, because here’s what gets glossed over:

Try installing a VM from a regular DVD. Go ahead. Please.

Under Install Media URL, I’ve tried
/media/Fedora 8 x86_64 DVD
/media/Fedora8 (which I ln -s to ‘Fredora 8 x86_64 DVD’)
file:///media/Fedora8
/dev/scd0 (the DVD device)

/dev/scd0 does spin the drive, but then vaguely complains it can not find what it needs…

It appears you

OK, pop in a Fedora 8 DVD
5 vivek 01.10.08 at 4:11 am: Scott,

I’m sorry to hear it didn’t work out for you. These instructions are only tested on CentOS 5.0 and Fedora 7. I’ve already mentioned the fact.
6 nevyn 01.20.08 at 4:02 am: What would have been helpful is if you had:
a) included more information than “follow on screen instructions” such as a idea what sort of information we should be putting in a particular field. For example, if I wanted to install ubuntu-server, what would the URL be?
b) Included the instructions for installing off local media – as far as I know, you can’t install directly off dvd or cd but can off nfs so if you export the cd/dvd via nfs and then use the url for the nfs share you’d be sweet.
7 quequotion 11.14.08 at 11:54 am: this is a really poor and incomplete guide.

first of all, it only works for those lucky few who get to use a graphical interface. professionals in the field, who must conserve resources and minimize infrastructure, have absolutely no use for virt-manager.

second… there simply has to be more to it.
8 Piyush 12.24.08 at 12:31 pm: Vivek, Can you please add stuff like:
Installation of XEN on non GUI system (with virt-console may be….)
How to create a VM and change resources .. etc…

Would be helpful ……….

Thanks in Adv!

- Piyush
9 Avalon 05.20.09 at 3:25 pm: Nice howto. Maybe not very thorough but gives an idea what to look for ( for noobs like me :)

wrt professionals with no gui… go read the source hackers ;p
10 Avalon 05.20.09 at 3:35 pm: (sorry for double posting)
Let me give you a hint though – vnc
11 Greg 12.05.09 at 8:10 pm: OK, I am absolutely new to setting up a virtual machine. I used the command below and received an error that I have no idea what it means:

Paravirtualized guests cannot install off cdrom media.

virt-install \
> –name Fedora-12 \
> –ram 1000 \
> –file /data/vm/Fedora-12 \
> –network network:default \
12 rchilro 01.08.10 at 10:47 pm: it is a fantastic tutorial!!!!!!!! right to the point!

i wound suggest to include a note to edit the /etc/grub.conf and change the ‘default=0′ or it will start the old kernel.

cheers!

rchilro
13 Kartik Vashishta 02.03.10 at 4:24 pm: The option to install the virtual host via CD/DVD is grayed out for me, the only options I have is to install via the internet. Did I miss some step to add the dvd drive to the virtual machine. Please help.