Virtualization With KVM On A Fedora 12 Server
Version 1.0
Author: Falko Timme 
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This guide explains how you can install and use KVM for creating and running virtual machines on a Fedora 12 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 Fedora 12 server 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 a Fedora 12 desktop here.
2 Installing KVM
Fedora 12 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 nopl 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 nopl 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
yum install kvm qemu libvirt python-virtinst
Then start the libvirt daemon:
/etc/init.d/libvirtd start
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...
yum install bridge-utils
... and configure a bridge.
I disable Fedora's NetworkManager and enable "normal" networking. NetworkManager is good for desktops where network connections can change (e.g. LAN vs. WLAN), but on a server you usually don't change network connections:
chkconfig NetworkManager off
chkconfig --levels 35 network on
/etc/init.d/network restart
Check your /etc/resolv.conf if it lists all nameservers that you've previously configured:
cat /etc/resolv.conf
If nameservers are missing, run
system-config-network
and add the missing nameservers again.
To configure the bridge, create the file /etc/sysconfig/network-scripts/ifcfg-br0 (please use the BOOTPROTO, DNS1 (plus any other DNS settings, if any), GATEWAY, IPADDR, NETMASK and SEARCH values from the /etc/sysconfig/network-scripts/ifcfg-eth0 file):
vi /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0 TYPE=Bridge BOOTPROTO=static DNS1=145.253.2.75 GATEWAY=192.168.0.1 IPADDR=192.168.0.100 NETMASK=255.255.255.0 ONBOOT=yes SEARCH="example.com" |
Modify /etc/sysconfig/network-scripts/ifcfg-eth0 as follows (comment out BOOTPROTO, DNS1 (and all other DNS servers, if any), GATEWAY, IPADDR, NETMASK, and SEARCH and add BRIDGE=br0):
vi /etc/sysconfig/network-scripts/ifcfg-eth0
# Networking Interface DEVICE=eth0 #BOOTPROTO=none #DNS1=145.253.2.75 #GATEWAY=192.168.0.1 HWADDR=00:1e:90:f3:f0:02 #IPADDR=192.168.0.100 #NETMASK=255.255.255.0 ONBOOT=yes TYPE=Ethernet IPV6INIT=no USERCTL=no BRIDGE=br0 |
Then reboot the system:
reboot
After the reboot, 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:113 errors:0 dropped:0 overruns:0 frame:0
TX packets:91 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:16520 (16.1 KiB) TX bytes:11889 (11.6 KiB)
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:136 errors:0 dropped:0 overruns:0 frame:0
TX packets:98 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:22152 (21.6 KiB) TX bytes:14147 (13.8 KiB)
Interrupt:28 Base address:0x2000
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:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:746 (746.0 b) TX bytes:746 (746.0 b)
virbr0 Link encap:Ethernet HWaddr E2:54:14:EA:7A:01
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
inet6 addr: fe80::e054:14ff:feea:7a01/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:29 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:5156 (5.0 KiB)
[root@server1 ~]#
3 Installing virt-manager On Your Fedora 12 Desktop
Fedora 12 Desktop:
We need a means of connecting to the graphical console of our guests - we can use virt-manager for this. I'm assuming that you're using a Fedora 12 desktop.
Become root...
su
... and run...
yum install virt-manager
... to install virt-manager.
(If you're using an Ubuntu 9.10 desktop, you can install virt-manager as follows:
sudo aptitude install virt-manager
)
4 Creating A Debian Lenny Guest (Image-Based)
Fedora 12 KVM Host:
Now let's go back to our Fedora 12 KVM host.
Take a look at
man virt-install
to learn how to use it.
To create a Debian Lenny guest (in bridging mode) with the name vm10, 512MB of RAM, two virtual CPUs, and the disk image ~/vm10.qcow2 (with a size of 12GB), insert the Debian Lenny Netinstall CD into the CD drive and run
virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 -f ~/vm10.qcow2 -s 12 -c /dev/cdrom --vnc --noautoconsole --os-type linux --os-variant debianlenny --accelerate --network=bridge:br0 --hvm
Of course, you can also create an ISO image of the Debian Lenny Netinstall CD...
dd if=/dev/cdrom of=~/debian-500-amd64-netinst.iso
... and use the ISO image in the virt-install command:
virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 -f ~/vm10.qcow2 -s 12 -c ~/debian-500-amd64-netinst.iso --vnc --noautoconsole --os-type linux --os-variant debianlenny --accelerate --network=bridge:br0 --hvm
The output is as follows:
[root@server1 ~]# virt-install --connect qemu:///system -n vm10 -r 512 --vcpus=2 -f ~/vm10.qcow2 -s 12 -c ~/debian-500-amd64-netinst.iso --vnc --noautoconsole --os-type linux --os-variant debianlenny --accelerate --network=bridge:br0 --hvm
Starting install...
Creating storage file... | 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 ~]#
