Virtualization in Grid'5000

See also: KVM | KVM on production environment

Purpose

This page presents ways to use KVM on production image.

Usage

First, submit the job using habitual oarsub command

jdoe@fnancy:~$ oarsub -I

Copy the kvm disk image to /tmp on the node

jdoe@griffon-37:~$ cp /grid5000/images/KVM/squeeze-x64-base.qcow2 /tmp/

Create Tun/Tap interface for your guest OS

jdoe@griffon-37:~$ sudo create_tap

• Tun/Tap interfaces are listed by issuing the command /sbin/ifconfig.

jdoe@griffon-37:~$ /sbin/ifconfig

[...]
tap0      Link encap:Ethernet  HWaddr 00:16:3e:db:c6:41  
          inet6 addr: fe80::58ff:a4ff:fe97:c6a8/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:29435 overruns:0 carrier:0
          collisions:0 txqueuelen:500 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

	Note
	Create one Tun/Tap interface per guest OS.

Generate a random mac address for the Tun/Tap interface

• Use the following script

jdoe@griffon-37:~$ export MACADDR=`random_mac`

	Note
	The first three octets are important (identification for the virtualized network). Don't change it.

Now, you can run the guest OS using kvm

jdoe@griffon-37:~$ screen kvm -m 512 -hda /tmp/squeeze-x64-base.qcow2 -net nic,macaddr=$MACADDR -net tap,ifname=tap0,script=no -nographic

	Note
	In this example, tap0 is the name of our Tun/Tap interface. Adapt it with the Tun/Tap name on witch you want to attach your guest OS.

Or, you can start the guest OS using libvirt

• Edit the domain file

eg : domain.xml

 <domain type='kvm'>
  <name>squeeze</name>
  <memory>524288</memory>
  <vcpu>1</vcpu>
  <os>
    <type arch="x86_64">hvm</type>
  </os>
  <clock sync="localtime"/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/bin/kvm</emulator>
    <disk type='file' device='disk'>
      <driver type='qcow2'/>
      <source file='/tmp/squeeze-x64-base.qcow2'/>
      <target dev='vda' bus='virtio'/>
    </disk>
    <disk type='file' device='cdrom'>
      <source file='/tmp/kvm-context.iso'/>
      <target dev='vdb' bus='virtio'/>
      <readonly/>
    </disk>
    <interface type='ethernet'>
      <target dev='tap0'/>
      <script path='no'/>
      <mac address='00:16:3e:78:b8:04'/>
    </interface>
    <serial type='pty'>
      <source path='/dev/ttyS0'/>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <source path='/dev/ttyS0'/>
      <target port='0'/>
    </console>
  </devices>
 </domain>

• Now, the guest OS can be started.

jdoe@griffon-37:~$ virsh create domain.xml

• You can use virsh to manage your guest OS.

jdoe@griffon-37:~$ virsh list 
jdoe@griffon-37:~$ virsh console squeeze

	Note
	You can use the script /usr/local/bin/random_mac to generate a mac address.

Misc notes

• For the deployment of an important number of guest OS, you can use the subnet reservation. See also the virtual network interlink.
• Manage the console for all your guest OS with Screen
• Account: root:grid5000
• Use tunctl if you need to delete a Tun/Tap device.

jdoe@griffon-37:~$ /usr/sbin/tunctl -d tap0

• Some clusters don't have virtualization support in the BIOS. To check :

jdoe@griffon-37:~$ egrep '^flags.*(vmx|svm)' /proc/cpuinfo