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

Posted on in Categories CentOS, High performance computing, Howto, Linux, Linux Virtualization, RedHat/Fedora Linux, xen last updated October 18, 2007

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 &

CentOS XEN Virtual machine manager
CentOS XEN Virtual machine 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.

Fig.01: Centos Xen Virtualization Installation
Fig.01: Centos Xen Virtualization Installation

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:

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

26 comment

  1. “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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. Hi, Im running a centos 5 64bit +cpanel with about 15 hosting accounts running in it. There are few of them wanted windows hosting to run asp vb and etc. So i cant get a dedi or vps just for 2 or 3 accounts, so i have heard about using xen to run multiple vps on it, my questions are :

    1) can i install xen to run windows without interupting cpanel and other hosting accounts?

    2)Can i do all these installation from command prompt? how about windows OS? without CD?

    Thanks

  8. I am having the same trouble as Kartil Vashishta, my vm manager does not allow me to install via CD/DVD, this is right after an install of centos in text mode then switching over to gui (because of an intel gma problem) just though I would add that although I don’t think that is what is causing it, also I am using the newest release 5.4 I think.

  9. i think. i can do that. 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

    Reply

    1. virt-install –name VM-Windows2008-1 –ram 4096 –vcpus 2 –disk path=/home/img/Windows2008.img,size=40 –network=bridge:BRIDGE –vnc –vncport=5911 –os-variant win2k8 –cdrom /home/iso/Windows2008_r2*.iso -d

      can you help me, thankyou~

  10. Create a Host and 4 VM Guests using XEN (not Virtual Box):
    a. The Host:
    i. CentOS Linux
    ii. Network address should be: 1.0.0.1
    iii. SSH and VNC should be enabled
    iv. Should be the Gateway to the Internet in both directions for the Guests – so, you shouldn’t be able to access the guests using SSH or VNC directly, you have to access them through the Host only.
    b. The Guests:
    i. RedHat Linux.
    ii. Network address should be: 10.0.0.1
    iii. SSH and VNC should be enabled
    iv. Two Guests should be installed using Para Technique, and two should use the Full Virtualization technique
    v. We need to be able to use HHD for two of them, and LVM for the other two
    vi. Install Apache Web Server on one of the guests – we should be able to access the web server from outside

    plz. some one help me i can do this as a concept 🙂

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