[libvirt-users] Pool, iSCSI and guest start

[Nicolas Greneche]

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Dave Allan wrote:
> On 03/19/2010 04:44 AM, Nicolas Greneche wrote:
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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
> 
> Are the appropriate network interfaces started/configured?
> 
> 

Yes, I ran an ifconfig, route, iptables to see if network interfaces are
well started and if there are no iptable rules loaded. All seems to be
OK. I launched all those commands before start-stop-daemon of libvirtd.

- --
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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