[libvirt-users] Pool, iSCSI and guest start

[Nicolas Greneche]

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Dave Allan wrote:
> On 03/17/2010 06:38 AM, Nicolas Greneche wrote:
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>>
>> Hi,
>>
>> Former user of Xen and newbie in kvm/qemu/libvirt stuff, I give it a try
>> on my network ;-)
>>
>> I need to run a VM with iSCSI target attached.
>>
>> I did it this way :
>>
>> 1) Creation of iscsi pool (equa.xml) :
>>
>> <pool type="iscsi">
>> <name>equalog</name>
>> <source>
>> <host name="10.10.0.1"/>
>> <device
>> path="iqn.2001-05.com.equallogic:0-8a0906-4992c7f05-39c000000114b8fc-vglog"/>
>>
>> </source>
>> <target>
>> <path>/dev/disk/by-path</path>
>> </target>
>> </pool>
>>
>> This pool start smoothly (when open-iscsi started), no problems. An
>> entry is created in /dev/disk/by-path/ related to iscsi target.
>>
>> 2) I flagged it autostart :
>>
>> root at sandi:~# virsh pool-autostart equalog
>> Pool equalog marked as autostarted
>>
>> root at sandi:~# virsh pool-list
>> Name                 State      Autostart
>> - -----------------------------------------
>> equalog              active     yes
>>
>> 3) In my guest VM, I have following section :
>>
>>      <disk type='block' device='disk'>
>>        <driver name='qemu'/>
>>        <source
>> dev='/dev/disk/by-path/ip-10.10.0.1:3260-iscsi-iqn.2001-05.com.equallogic:0-8a0906-4992c7f05-39c000000114b8fc-vglog-lun-0'/>
>>
>>        <target dev='vdc' bus='virtio'/>
>>        <alias name='virtio2'/>
>>        <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
>> function='0x0'/>
>>      </disk>
>>
>> When I start VM, iscsi target is availaible.
>>
>> The snag is that when I reboot the host, the pool is not automatically
>> started (making it impossible to autostart VM relying on this iscsi
>> volume).
>>
>> I verified that open-iscsi is started first. Startup script is localised
>> in /etc/rcS.d which is prior to /etc/rc2.d (my default runlevel).
>> Libvirtd is started in rc2.d and not mentionned in rcS.d.
>>
>> My questions are :
>> - - Is this the correct way to attach iscsi volume to a guest ?
>> - - Did I missed something to have iscsi pool autostart working at boot
>> time ?
> 
> You're doing everything right, so it's odd that the pool isn't
> autostarting.  Does the pool autostart properly if you restart libvirtd
> when the system is fully booted?
> 
> Dave
> 
> 

Hi Dave,

It's a very odd problem. Making network debugging with tcpdump makes me
see that my network stack doesn't receive "arp reply" related to my target.

If I add an ARP entry by hand in cache or a sleep just before libvirtd
start function in startup script it works like a charm.

Very odd, I asked debian package maintainers for help :

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=574358

Regards,

- --
Nicolas Greneche -  RSSI et Sysadmin
Centre de Ressources Informatiques (CRI)
Doctorant au sein du projet SDS - www.sds-project.fr
Mail : nicolas.greneche_(at)_univ-orleans.fr
GPG  : http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x5FEBD0EF

Universite d'Orleans            Web  : http://blog.garnett.fr
Batiment 3IA - 2e etage         Tel  : 02 38 49 25 26
6 rue Leonard de Vinci
BP 6102 45061 ORLEANS Cedex 2
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