Virtualization With KVM On A Debian Squeeze Server
Version 1.0
Author: Falko Timme
This guide explains how you can install and use KVM for creating and running virtual machines on a Debian Squeeze server. I will show how to create image-based virtual machines and also virtual machines that use a logical volume (LVM). KVM is short for Kernel-based Virtual Machine and makes use of hardware virtualization, i.e., you need a CPU that supports hardware virtualization, e.g. Intel VT or AMD-V.
I do not issue any guarantee that this will work for you!
1 Preliminary Note
I'm using a machine with the hostname server1.example.com and the IP address 192.168.0.100 here as my KVM host.
We also need a desktop system where we install virt-manager so that we can connect to the graphical console of the virtual machines that we install. I'm using an Ubuntu 10.10 desktop here.
2 Installing KVM
Debian Squeeze KVM Host:
First check if your CPU supports hardware virtualization - if this is the case, the command
egrep '(vmx|svm)' --color=always /proc/cpuinfo
should display something, e.g. like this:
root@server1:~# egrep '(vmx|svm)' --color=always /proc/cpuinfo
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall
nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 3dnowprefetch
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall
nx mmxext fxsr_opt rdtscp lm 3dnowext 3dnow rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 3dnowprefetch
root@server1:~#
If nothing is displayed, then your processor doesn't support hardware virtualization, and you must stop here.
To install KVM and virtinst (a tool to create virtual machines), we run
apt-get install kvm qemu-kvm libvirt-bin virtinst
Afterwards we must add the user as which we're currently logged in (root) to the groups libvirt and kvm:
adduser `id -un` libvirt
adduser `id -un` kvm
You need to log out and log back in for the new group membership to take effect.
To check if KVM has successfully been installed, run
virsh -c qemu:///system list
It should display something like this:
root@server1:~# virsh -c qemu:///system list
Id Name State
----------------------------------
root@server1:~#
If it displays an error instead, then something went wrong.
Next we need to set up a network bridge on our server so that our virtual machines can be accessed from other hosts as if they were physical systems in the network.
To do this, we install the package bridge-utils...
apt-get install bridge-utils
... and configure a bridge. Open /etc/network/interfaces:
vi /etc/network/interfaces
Before the modification, my file looks as follows:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
#allow-hotplug eth0
#iface eth0 inet dhcp
auto eth0
iface eth0 inet static
address 192.168.0.100
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.1
|
I change it so that it looks like this:
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
#allow-hotplug eth0
#iface eth0 inet dhcp
auto eth0
iface eth0 inet manual
auto br0
iface br0 inet static
address 192.168.0.100
network 192.168.0.0
netmask 255.255.255.0
broadcast 192.168.0.255
gateway 192.168.0.1
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off
|
(Make sure you use the correct settings for your network!)
Restart the network...
/etc/init.d/networking restart
... and run
ifconfig
It should now show the network bridge (br0):
root@server1:~# ifconfig
br0 Link encap:Ethernet HWaddr 00:1e:90:f3:f0:02
inet addr:192.168.0.100 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::21e:90ff:fef3:f002/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5 errors:0 dropped:0 overruns:0 frame:0
TX packets:9 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:310 (310.0 B) TX bytes:838 (838.0 B)
eth0 Link encap:Ethernet HWaddr 00:1e:90:f3:f0:02
inet6 addr: fe80::21e:90ff:fef3:f002/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:45364 errors:0 dropped:0 overruns:0 frame:0
TX packets:24634 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:66909993 (63.8 MiB) TX bytes:1988727 (1.8 MiB)
Interrupt:28
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:560 (560.0 B) TX bytes:560 (560.0 B)
root@server1:~#
3 Installing virt-viewer Or virt-manager On Your Ubuntu 10.10 Desktop
Ubuntu 10.10 Desktop:
We need a means of connecting to the graphical console of our guests - we can use virt-manager (see KVM Guest Management With Virt-Manager On Ubuntu 8.10) for this. I'm assuming that you're using an Ubuntu 10.10 desktop.
Run
sudo apt-get install virt-manager
to install virt-manager.
4 Creating A Debian Squeeze Guest (Image-Based) From The Command Line
Debian Squeeze KVM Host:
Now let's go back to our Debian Squeeze KVM host.
Take a look at
man virt-install
to learn how to use it.
We will create our image-based virtual machines in the directory /var/lib/libvirt/images/ which was created automatically when we installed KVM in chapter two.
To create a Debian Squeeze guest (in bridging mode) with the name vm10, 512MB of RAM, two virtual CPUs, and the disk image /var/lib/libvirt/images/vm10.img (with a size of 12GB), insert the Debian Squeeze Netinstall CD into the CD drive and run
virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 --disk path=/var/lib/libvirt/images/vm10.img,size=12 -c /dev/cdrom --vnc --noautoconsole --os-type linux --os-variant debiansqueeze --accelerate --network=bridge:br0 --hvm
Of course, you can also create an ISO image of the Debian Squeeze Netinstall CD (please create it in the /var/lib/libvirt/images/ directory because later on I will show how to create virtual machines through virt-manager from your Ubuntu desktop, and virt-manager will look for ISO images in the /var/lib/libvirt/images/ directory)...
dd if=/dev/cdrom of=/var/lib/libvirt/images/debian-6.0.0-amd64-netinst.iso
... and use the ISO image in the virt-install command:
virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 --disk path=/var/lib/libvirt/images/vm10.img,size=12 -c /var/lib/libvirt/images/debian-6.0.0-amd64-netinst.iso --vnc --noautoconsole --os-type linux --os-variant debiansqueeze --accelerate --network=bridge:br0 --hvm
The output is as follows:
root@server1:~# virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 --disk path=/var/lib/libvirt/images/vm10.img,size=12 -c /var/lib/libvirt/images/debian-6.0.0-amd64-netinst.iso --vnc --noautoconsole --os-type linux --os-variant debiansqueeze --accelerate --network=bridge:br0 --hvm
Starting install...
Allocating 'vm10.img' | 12 GB 00:00
Creating domain... | 0 B 00:00
Domain installation still in progress. You can reconnect to
the console to complete the installation process.
root@server1:~#