[one-users] iSCSI recipe

Ruben S. Montero rsmontero at opennebula.org
Wed Dec 5 02:45:03 PST 2012 

Yep, you are right already fixed in master [1]!

Thank you for your feedback :)

[1]http://dev.opennebula.org/issues/1679

On Wed, Dec 5, 2012 at 2:12 AM, Gary S. Cuozzo <gary at isgsoftware.net> wrote:
> It does appear that the SRC & DEST arguments are reversed.
>
> ----- Original Message -----
> From: "Ruben S. Montero" <rsmontero at opennebula.org>
> To: "Gary S. Cuozzo" <gary at isgsoftware.net>
> Cc: users at lists.opennebula.org
> Sent: Monday, December 3, 2012 5:35:47 AM
> Subject: Re: [one-users] iSCSI recipe
>
> Hi
>
> Yes the pre-post scripts are those of the system datastore. In fact,
> you are dealing with disk images inside the system datastore. I agree
> this can be misleading, but think that in general you may have images
> from different datastores that may need different things.
>
> So the pre-post scripts are those of the system data-store, but you do
> not follow the system datastore type (i.e. iSCSI things do fit in the
> shared pre/post scripts). Also note that you should use the VM
> template to iterate through the disks and perform the pre-post
> operations over them.
>
> About SRC/DST arguments, do you refer to the src and dst hosts, right?
> is that a bug that we need to address?
>
> Cheers and thank you for your great feedback!
>
> Ruben
>
>
>
> On Sun, Dec 2, 2012 at 3:55 PM, Gary S. Cuozzo <gary at isgsoftware.net> wrote:
>> Thanks Laurent, I'll take the same route.  Also thanks for the SRC & DST tip.
>>
>> ----- Original Message -----
>> From: "Laurent Grawet" <laurent.grawet at uclouvain.be>
>> To: "Gary S. Cuozzo" <gary at isgsoftware.net>
>> Cc: "Ruben S. Montero" <rsmontero at opennebula.org>, "christopher barry" <cbarry at rjmetrics.com>, users at lists.opennebula.org
>> Sent: Sunday, December 2, 2012 5:53:01 AM
>> Subject: Re: [one-users] iSCSI recipe
>>
>> Hi Gary,
>>
>> On 02/12/12 07:44, Gary S. Cuozzo wrote:
>>> Hi Ruben,
>>> I'm finally back to work on my opennebula project.  I just upgraded to 3.8.1 and starting to modify my drivers to use the new pre/postmigrate scripts.  I see they only get called for the TM of the system datastore ("shared" in my case).  Is there a reason that the pre/post scripts can't be called on the TM for the driver of the particular disk that is being migrated?  I have 2 different drivers, a ZFS-iSCSI and a ZFS-NFS driver that both need to perform tasks before & after migration.  If one called the pre/post script for the specific TM, I could put all the logic together for each driver.
>>>
>>> I guess what I could do for now is modify the shared driver to check the TM of the disk and then call the appropriate driver script from there.
>>>
>>> What do you think?
>>>
>>> Thanks for adding the feature.
>>> gary
>>
>> There is a workaround for this. I have put the pre/post scripts inside
>> my driver directory. I call them from the pre/post scripts of the system
>> datastore. Then I check TM_MAD inside my scripts using DS_ID.
>> One thing I have noticed, SRC and DST args are swapped.
>>
>> Cheers,
>>
>> Laurent
>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "Ruben S. Montero" <rsmontero at opennebula.org>
>>> To: "Laurent Grawet" <laurent.grawet at uclouvain.be>
>>> Cc: "Gary S. Cuozzo" <gary at isgsoftware.net>, "christopher barry" <cbarry at rjmetrics.com>, users at lists.opennebula.org
>>> Sent: Wednesday, October 31, 2012 6:41:44 PM
>>> Subject: Re: [one-users] iSCSI recipe
>>>
>>> Hi
>>>
>>> Please note that the post/pre-migrate scripts are those from the
>>> system datastore. Probably, they should be put in shared or ssh dir
>>> and not in iscsi.
>>>
>>>
>>> The description of the arguments are in here:
>>> http://opennebula.org/documentation:rel3.8:sd
>>>
>>> If you need to iterate over the disks in the template, you may be need
>>> to use ruby or pythonn for this script. Or, if you assume that there
>>> are no more than,let say 5 disks,you can get the first 5 diks using
>>> VM/TEMPLATE/DISK[DISK_ID=0] and so on and work on them if they are
>>> defined....
>>>
>>>
>>> Cheers
>>>
>>>
>>> Ruben
>>>
>>>
>>>> On Fri, Aug 17, 2012 at 9:43 AM, Gary S. Cuozzo <gary at isgsoftware.net>
>>>> wrote:
>>>>>> Excellent, thanks.
>>>>>>
>>>>>> ________________________________
>>>>>> 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 7:19:23 PM
>>>>>>
>>>>>> Subject: Re: [one-users] iSCSI recipe
>>>>>>
>>>>>> 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
>>>>>>>>> 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
>>>>>>> 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
>>>>>>
>>>>>
>>>>
>>>> --
>>>> Laurent Grawet
>>>> Infrastructures de production du système d'information (LS/SGSI/SIPR)
>>>> Université Catholique de Louvain - UCL
>>>> Tél : +32 (0)10 47 38 44
>>>>
>>>>
>>>
>>>
>>> --
>>> 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
>>
>>
>> --
>> Laurent Grawet
>> Infrastructures de production du système d'information (LS/SGSI/SIPR)
>> Université Catholique de Louvain - UCL
>> Tél : +32 (0)10 47 38 44
>>
>>
>> _______________________________________________
>> 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
www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula

More information about the Users mailing list