Virtualization in Grid'5000

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.img /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 5a:ff:a4:97:c6:a8  
          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:~$ MACADDR="00:16:3e:$(dd if=/dev/urandom count=1 2>/dev/null | md5sum | sed 's/^\(..\)\(..\)\(..\).*$/\1:\2:\3/')"; echo $MACADDR

	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.img -net nic,macaddr=$MACADDR -net tap,ifname=tap0,script=no -nographic

Or, you can start the guest OS using libvirt

• Edit the domain file

eg : domain.xml

<domain type='kvm'>
  <name>squeeze-vm1</name>
  <memory>524288</memory>
  <vcpu>1</vcpu>
  <os>
    <type arch="x86_64">hvm</type>
  </os>
  <clock sync="localtime"/>
  <devices>
    <disk type='file' device='disk'>

      <target dev='hda'/>
    </disk>
    <interface type='ethernet'>
      <target dev='tap0'/>
      <script path='no'/>
      <mac address='00:16:3e:82:a6:ea'/>
    </interface>
    <graphics type='vnc' port='5900'/>
  </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 

	Note
	Use the mac address generated with the script

Misc notes

• Manage the console for all your guest OS with Screen
• Use tunctl if you need to delete a Tun/Tap device.

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