[one-users] iSCSI recipe

Thu Aug 16 16:19:23 PDT 2012

Ok

Know I see the point. We are doing something similar for
attaching/detaching an specific script is executed before and after the
hypervisor. So I guess this could be added. I've filled an issue for this
and plan it in future versions

http://dev.opennebula.org/issues/1419

Meanwhile, as you probably had already found out, you can modify the
migrate script to embed those "TM scripts".

Cheers

Ruben

On Thu, Aug 16, 2012 at 5:40 PM, Gary S. Cuozzo <gary at isgsoftware.net>wrote:

> Is there a reason that ONE can't call a TM script with the source host,
> dest host, vm template, etc. when the migrate command is executed?
>
> While ONE can't orchestrate the migration, it can at least notify the TM
> of the migration in advance.  That would allow me to grab the info I need
> from the template and fire off the login or rescan on the dest host.  ONE
> has got to know this info in order to even notify libvirt/KVM to do the
> migration.  So just call a TM script before issuing the libvirt command and
> abort if the script returns error.
>
> Logout is not as critical to me.  Worst case I have some hosts which iSCSI
> sessions which are not in use.  The ideal scenario would be to be able to
> have some sort of TM script that gets called after ONE detects successful
> migration, but I could work around that on my own if it were not the case.
>
> ------------------------------
> *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 11:28:27 AM
>
> *Subject: *Re: [one-users] iSCSI recipe
>
> 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
>>>
>>>
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users at lists.opennebula.org
>>> 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
>>> <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org>
>>> www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
>>>
>>>
>>
>> _______________________________________________
>> Users mailing list
>> Users at lists.opennebula.org
>> 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
>
>
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> 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
> <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org>
> www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
>
>
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