[one-users] tune 'onevm saveas' behavior for OpenVZ

[Tino Vazquez]

Dear Nikolay,

I think the image.rb approach won't work anyway, because it is
executed on the DONE state, when the transfer manager already staged
back the disk.i's already to the ONE FrontEnd.

So I guess where you really want to set this tar operation is in the
TM scripts. Take a look at src/tm_mad/ssh/tm_mv.sh. The last lines
are:

--
exec_and_log "$SSH $DST_HOST mkdir -p $DST_DIR"
exec_and_log "$SCP -r $SRC $DST"
exec_and_log "$SSH $SRC_HOST rm -rf $SRC_PATH"
--

you have to ensure that $SRC is the tar.gz of the modified openVZ disk
(that is, with the modifications after running the VM). You will need
also to modify src/tm_mad/nfs/tm_mv.sh to allow for shared storage
configurations.

You can create  new TMs (tm_ssh_openvz and tm_nfs_openvz) by basically
using all the existing tm_* scripts, and including the modified
tm_mv.sh

Hope it helps,

-Tino


--
Constantino Vázquez Blanco, MSc
OpenNebula Major Contributor
www.OpenNebula.org | @tinova79



On Tue, Aug 23, 2011 at 2:38 PM,  <knawnd at gmail.com> wrote:
> Tino Vazquez wrote on 23/08/11 14:58:
>>>
>>> So for now I would like to make a 'onevm saveas' command work with OpenVZ
>>> VMs as well as if the SAVE sub-attribute is set to yes for OpenNebula
>>> 2.2.1.
>>> As far as I understand both these features trigger
>>> $ONE_LOCATOIN/share/hooks/image.rb script. So in order to achieve a
>>> desired
>>> behavior a command like 'tar -czf $VM_DIR/<VMID>/images/disk.0 -C
>>> /vz/private/<VMID>/ *' must be executed in the beginning of that hook
>>> (image.rb) what would replace the original disk.0 file. Is that correct?
>>> I would appreciate any help on that.
>>
>> Yes, this seems like a good approach. Have you tried it out? It look fine
>> to me.
>
> I started to modify $ONE_LOCATION/share/hooks/image.rb file but then
> realized that hooks ($ONE_LOCATOIN/share/hooks/image.rb) is executed locally
> on FN whereas the VM directory packaging/archiving has to be done remotely
> i.e. on CNs. So adding to that hook something that needs to be done remotely
> (like
> ssh root@<CN> "sudo tar -Sp -C -czf #{source_path} ." would break remote and
> local hooks logic as I wrote before in [1]
>> So I see not so much possibilities:
>> 1) add the execution of tar command on remote node in image.rb hook which
>> is executed on local (front-end) node i.e. such approach breaks the
>> local/remote hooks logic;
>> 2) create one more custom hook what has to be executed on remote node
>> and what would archive VM working dir. But there are several issues here:
>> - how one can make sure that custom hook will be executed before
>> image.rb one since both of them should be triggered when VM reaches the
>> DONE state,
>> - how make that custom hook trigger only upon 'onevm saveas' command
>> execution or if SAVE sub-attribute of DISK attribute is set to YES.
>
> So I am stuck at that point.
>
> As always any help on that is highly appreciated!
>
> Regards,
> Nikolay.
>
> [1] http://article.gmane.org/gmane.comp.distributed.opennebula.user/3948
>
>>
>> Regards, and many thanks for the detailed emails (it does help a long
>> way in understanding the issue ;))
>>
>> -Tino
>