INTRODUCTION

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We will create our image-based virtual machines in the directory /var/lib/libvirt/images/ which was created automatically when we installed libvirt.

INSTALLATION

CentOS has a nice tool called virt-install with which we can create virtual machines for Xen. To start it, we simply run

#virt-install  -–prompt  -–network  bridge=br0  -–virt-type=xen

(We must specify our network bridge with –network bridge=br0 so that the virtual machine uses our network bridge which we created in previous blog xen installation).

The tools asks a few questions before it creates a virtual machine. I want to call my first virtual machine vm01, with 1024MB RAM and a disk size of 10GB. I want to store it in the file /var/lib/libvirt/images/sathishvm.img:

Would you like a fully virtualized guest (yes or no)? This will allow you to run unmodified operating systems.
<– no
What is the name of your virtual machine?
<– sathishvm
How much RAM should be allocated (in megabytes)?
<– 1024
What would you like to use as the disk (file path)?
<– /var/lib/libvirt/images/sathishvm.img
How large would you like the disk (/var/lib/libvirt/images/vm01.img) to be (in gigabytes)?
<– 10
What is the install URL?
<– http://ftp.tu-chemnitz.de/pub/linux/centos/6.3/os/x86_64

In this chapter I want to create a paravirtualized guest, not a fully (hardware) virtualized guest, that’s why I answer the first question with no.

As install URL, you should specify a mirror close to you where the installer can download all files needed for the installation of CentOS 6.3 in our virtual machine.

After we have answered all questions, virt-install starts the normal CentOS 6.3 installer (in text mode) in our sathishvm virtual machine.

1

After the installation, we stay at the sathishvm console.If you are at the console, or CTRL+5 if you’re using PuTTY. You will then be back at the dom0console.

2 u

Run

#virsh console sathishvm

to log in on that virtual machine again (type CTRL+] if you are at the console, or CTRL+5 if you’re using PuTTY to go back to dom0), or use an SSH client to connect to it.

To get a list of running virtual machines, type

#virsh list
Id Name                 State
———————————-
0 Domain-0             running
2 sathishvm                 idle
y

To shut down sathish, do this:

#virsh shutdown sathishvm

To start sathishvm again, run

#virsh start sathishvm

Here are the most important Xen commands:

virsh start <name> – Start a virtual machine.
virsh shutdown <name> – Stop a virtual machine.
virsh destroy <name> – Stop a virtual machine immediately without shutting it down. It’s as if you switch off the power button.
virsh list – List all running systems.
virsh console <name> – Log in on a virtual machine.
virsh help – List of all commands.