Virtualization With KVM On A Fedora 13 Server

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Submitted by falko (Contact Author) (Forums) on Thu, 2010-06-17 17:10. :: Fedora | KVM | Virtualization

Virtualization With KVM On A Fedora 13 Server

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Author: Falko Timme <ft [at] falkotimme [dot] com>
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Last edited 06/14/2010

This guide explains how you can install and use KVM for creating and running virtual machines on a Fedora 13 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 13 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 13 desktop here.

 

2 Installing KVM

Fedora 13 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 qemu-kvm

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 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
DNS2=8.8.8.8
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

# nVidia Corporation MCP77 Ethernet
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
#DNS2=8.8.8.8
TYPE=Ethernet
IPV6INIT=no
USERCTL=no
PREFIX=24
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
NAME="System eth0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
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:44 errors:0 dropped:0 overruns:0 frame:0
          TX packets:61 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:7116 (6.9 KiB)  TX bytes:9437 (9.2 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:59 errors:0 dropped:0 overruns:0 frame:0
          TX packets:36 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:11062 (10.8 KiB)  TX bytes:5433 (5.3 KiB)
          Interrupt:28 Base address:0xe000

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:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

virbr0    Link encap:Ethernet  HWaddr 22:E3:B3:E8:87:8C
          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:3306 (3.2 KiB)

[root@server1 ~]#

 

3 Installing virt-manager On Your Fedora 13 Desktop

Fedora 13 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 13 desktop.

Become root...

su

... and run...

yum install virt-manager libvirt qemu-system-x86

... to install virt-manager.

(If you're using an Ubuntu 10.04 desktop, you can install virt-manager as follows:

sudo aptitude install virt-manager

)

 

4 Creating A Debian Lenny Guest (Image-Based)

Fedora 13 KVM Host:

Now let's go back to our Fedora 13 KVM host.

Take a look at

man virt-install

to learn how to use it.

I want to create my virtual machines in the directory /vm (they cannot be created in the /root directory because the qemu user doesn't have read permissions in that directory), so I have to create it first:

mkdir /vm

(If you try to create a virtual machine in the /root directory, you will get errors similar to this one:

[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 vm10.qcow2                                   |  12 GB     00:00
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/2
qemu: could not open disk image /root/vm10.qcow2: Permission denied

Domain installation may not have been
 successful.  If it was, you can restart your domain
 by running 'virsh start vm10'; otherwise, please
 restart your installation.
ERROR    internal error Process exited while reading console log output: char device redirected to /dev/pts/2
qemu: could not open disk image /root/vm10.qcow2: Permission denied
Traceback (most recent call last):
  File "/usr/sbin/virt-install", line 972, in <module>
    main()
  File "/usr/sbin/virt-install", line 834, in main
    start_time, guest.start_install)
  File "/usr/sbin/virt-install", line 896, in do_install
    dom = install_func(conscb, progresscb, wait=(not wait))
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 798, in start_install
    return self._do_install(consolecb, meter, removeOld, wait)
  File "/usr/lib/python2.6/site-packages/virtinst/Guest.py", line 899, in _do_install
    self.domain = self.conn.createLinux(install_xml, 0)
  File "/usr/lib64/python2.6/site-packages/libvirt.py", line 1147, in createLinux
    if ret is None:raise libvirtError('virDomainCreateLinux() failed', conn=self)
libvirtError: internal error Process exited while reading console log output: char device redirected to /dev/pts/2
qemu: could not open disk image /root/vm10.qcow2: Permission denied

[root@server1 ~]#

)

To create a Debian Lenny guest (in bridging mode) with the name vm10, 512MB of RAM, two virtual CPUs, and the disk image /vm/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 /vm/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=/vm/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 /vm/vm10.qcow2 -s 12 -c /vm/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 /vm/vm10.qcow2 -s 12 -c /vm/debian-500-amd64-netinst.iso --vnc --noautoconsole --os-type linux --os-variant debianlenny --accelerate --network=bridge:br0 --hvm


Starting install...
Creating domain...                                                       |    0 B     00:00
Domain installation still in progress. You can reconnect to
the console to complete the installation process.
[root@server1 ~]#


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