[one-users] iSCSI recipe

[Ruben S. Montero]

Note that OpenNebula cannot orchestrate the two libvirt/KVM hypervisors
doing the migration. When the first host is ready to stop running the VM
(memory has been sent to the second hypervisor, etc..) it executes the hook
(logout from the iSCSI server) and just right before starting rhe VM in the
second host the hook (login in the iSCSI server) is run. There is nothing
we can do to hook in that process.

We could however, include such scripts as part of the TM, distribute them
in the hosts, and put them in the right places...


Cheers






On Thu, Aug 16, 2012 at 1:48 PM, Gary S. Cuozzo <gary at isgsoftware.net>wrote:

> Thanks.  While I understand that the login/logout needs to happen on the
> host systems, I think that if ONE had it's own hook or, better IMO, a TM
> script that could be called before/after migration, the functionality could
> be contained within the drivers themselves.  Then I could just take my code
> (which is now sprinkled across several host machines) and put it in the TM
> where I think it better fits.  My DS/TM already make remote calls via SSH
> to the SAN & vm hosts, so this would still fit the model pretty nicely.
>
> I seem to remember that if the similar events for non-persistent images
> were called for persistent ones, I would be able to accomplish what I want.
>
> Let me know your thoughts.
>
> Thanks,
> gary
>
>
> ------------------------------
> *From: *"Ruben S. Montero" <rsmontero at opennebula.org>
> *To: *"Gary S. Cuozzo" <gary at isgsoftware.net>
> *Cc: *users at lists.opennebula.org
> *Sent: *Thursday, August 16, 2012 5:55:57 AM
> *Subject: *Re: [one-users] iSCSI recipe
>
> Hi
>
> For live-migrations the supported procedure is the libvirt hook, note that
> live migrations requires a close synchronization between the image
> movements, memory movements and the hypervisors. OpenNebula cannot perform
> the login/logout from the iSCSI sessions there. Cold migrations are handled
> by opennebula as part of the save and restore commands.
>
> Cheers
>
> Ruben
>
> On Sun, Aug 12, 2012 at 4:41 AM, Gary S. Cuozzo <gary at isgsoftware.net>wrote:
>
>> Hello,
>>
>>
>>>
>>> * Each host needs to attach to all iSCSI targets that are needed by
>>> guests running on the host. It's not entirely clear to me if ONE handles
>>> all that or not (assuming it does).
>>>
>>> ONE handles this by login/logout in an iSCSI session as needed
>>>
>>> My iSCSI setup uses a target for each virtual server, and multiple LUN's
>> per target (if the server has multiple disks).  I developed a custom driver
>> for it.  I don't know if I have a shortcoming in my driver, or maybe a
>> config issue on ONE, but I found that ONE did NOT handle the login/logout
>> on the host machines.  It was fine for the initial setup & deployment of
>> the vm, but live migrations did not cause my driver to initiate a login on
>> the receiving host and a logout on the transferring host.
>>
>> I ended up having to write a libvirt hook which scanned for new targets
>> to log them in.  It also rescanned all current targets to check if they had
>> new LUN's attached to them.  It works well and my vm's migrate just fine,
>> but I would prefer to have all this handled within ONE.
>>
>> What is the script that ONE calls in order to initiate the logins/logouts
>> as vm's migrate?
>>
>> Cheers,
>> gary
>>
>>
>>
>> _______________________________________________
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>> Users at lists.opennebula.org
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>>
>> --
>> Ruben S. Montero, PhD
>> Project co-Lead and Chief Architect
>> OpenNebula - The Open Source Solution for Data Center Virtualization
>> <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org>
>> www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
>>
>>
>
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> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>
>


-- 
Ruben S. Montero, PhD
Project co-Lead and Chief Architect
OpenNebula - The Open Source Solution for Data Center Virtualization
www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
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