[one-users] opennebula 3.8.1 + clvm

[Marlok Tamás]

Hi Jaime,

On Tue, Mar 12, 2013 at 12:16 PM, Jaime Melis <jmelis at opennebula.org> wrote:

> Hi Marlok,
>
> I agree with what you said, it would be much better to remove the
> requirement of CLVM, but I have a couple of concerns.  Let's see if we can
> find a solution to that together and decide if we can squeeze this one in
> for OpenNebula 4.0. Let me explain you the main problem I see.
>
> So, the main concern here is that in the shared_lvm TM drivers, you're
> operating directly on the frontend, and I think that will pose a problem if
> you want to have multiple LVM based datastores. I don't think it's a
> correct approach to force the OpenNebula admins to use the OpenNebula
> frontend as their LVM primary node.
>
> Yes, that's why I wrote this: "Or in the case of the one driver, the HOST
configured in the datastore config should execute this commands, but not
the host, running the VM." This is much more elegant.


> If you take a look at the DS/LVM drivers in the 'master' branch, you'll
> see that we extract the LVM primary node's hostname via the 'HOST'
> attribute of the datastore template [1]
> The problem is, that we don't have that information in the TM drivers. A
> solution would be to execute "onedatastore <id>" and extract the
> datatostore's LVM primary node for each operation: cp, ln, mvds, etc...
>
>


> One we have we have the name of the lvm primary node, we could follow your
> approach: operate (clone, create, remove, etc...) in that node and refresh
> it the nodes via lvscan and lvchange...
>
> any thoughts?
>
> [1]
> https://github.com/OpenNebula/one/blob/master/src/datastore_mad/remotes/lvm/clone#L56
>
> cheers,
> Jaime
>
>
> On Tue, Mar 12, 2013 at 11:41 AM, Marlok Tamás <tmarlok at sztaki.hu> wrote:
>
>> Hi Jaime,
>>
>> I examined the new lvm driver and compared it with shared_lvm.
>> I think, the only difference between them, is that in shared_lvm all of
>> the lvm commands are executed on the frontend (as we described in here:
>> http://wiki.opennebula.org/shared_lvm).
>> I would like to suggest, that you should consider to adapt this behaviour
>> in the new lvm driver.
>> (Or in the case of the one driver, the HOST configured in the datastore
>> config should execute this commands, but not the host, running the VM.)
>>
>> I can't see any drawback of this approach, but in this way, CLVM wouldn't
>> be necessary (refer the wiki article).
>>
>> We couldn't use CLVM for various reasons, but it would be much easier for
>> us (I think not just for us) if we could use the LVM driver already
>> implemented in OpenNebula, instead of shared_lvm.
>>
>> I see, that in the datastore driver scripts this is the current
>> behaviour. So only the tm scripts should be modified.
>>
>> If you can agree with this, but don't have the time for implementing,
>> just let me know, I can create a patch for you. Or if I am wrong let me
>> know that too :).
>>
>> Cheers,
>> Tamas
>>
>>
>> On Thu, Feb 21, 2013 at 6:52 PM, Jaime Melis <jmelis at opennebula.org>wrote:
>>
>>> Oops, you're right.
>>>
>>> Ok, so, can you test the upcoming LVM drivers for OpenNebula 4.0? It
>>> replaces snapshotting with cloning...
>>>
>>> just replace /var/lib/one/remotes/tm/lvm
>>> with the contents of:
>>> https://github.com/OpenNebula/one/tree/master/src/tm_mad/lvm
>>>
>>> and do "onehost sync" afterwards?
>>>
>>>
>>> On Thu, Feb 21, 2013 at 6:41 PM, Tobias Honacker
>>> <t.honacker at googlemail.com>wrote:
>>>
>>> > Hi Jaime,
>>> >
>>> > yes you are right. I posted the error log file with TM_MAD="lvm", too.
>>> I
>>> > tried both TM_MAD=shared and lvm.
>>> > I will try the links Mihály Héder already posted. But maybe you have
>>> got
>>> > any other ideas?
>>> >
>>> >
>>> > Best regards,
>>> > Tobias
>>> >
>>> >
>>> > Am 21.02.2013 um 18:37 schrieb Jaime Melis:
>>> >
>>> > Actually, it's "onedatastore update 100", not "onetemplate"... sorry
>>> >
>>> >
>>> > On Thu, Feb 21, 2013 at 6:22 PM, Jaime Melis <jmelis at opennebula.org
>>> >wrote:
>>> >
>>> >> Hi Tobias,
>>> >>
>>> >> your datastore template has the wrong TM_MAD. It should be
>>> TM_MAD="lvm"
>>> >> instead of TM_MAD="shared".
>>> >>
>>> >> You can fix it by doing "onetemplate update 100" and editing it
>>> in-place
>>>
>>
>>
>
>
> --
> Jaime Melis
> Project Engineer
> OpenNebula - The Open Source Toolkit for Cloud Computing
> www.OpenNebula.org | jmelis at opennebula.org
>
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