[one-users] perform "actions" on host just before Live Migration start??

fc lists fclists at pr-z.info
Thu May 17 12:02:15 PDT 2012


Brillant! ,

that will perfectly work in my case.

I wrote the DS and TM drivers to work out of a single Target (per project
more or less) with multiple LUNs ... that means that i only need 1 login
(that i actually can perform outside of ONE as well as during the LN so to
ensure that all hosts in the cluster are logged in to the ISCSI target) and
then i can use a simple "iscsiadm -m session -R" to pick device for VM that
is being live migrated.

The only thing that disappoint me a bit is that i will have to perform this
configuration outside of openebula ... but i see your point about it.
I think it might be useful to have some kind of hook related to the
live-migration command in opennebula, even if is just called when the
live-migrate command is called.
This way it would be possible to access the Image variables ...especially
Source.

Thanks for pointing the link anyway, in my case will really do the trick.

-FC



On Wed, May 16, 2012 at 10:46 AM, Jaime Melis <jmelis at opennebula.org> wrote:

> Hello,
>
> OpenNebula can't have control overt the internal live-migration process of
> the hypervisors. The iscsi actions should be perfectly synchronized with
> the live migration, otherwise an I/O error is likely to occur. That's the
> reason why this isn't out of the box supported with OpenNebula.
>
> I believe the correct way to approach this is through hypervisor hooks:
> http://libvirt.org/hooks.html#qemu_migration
>
> cheers,
> Jaime
>
> On Tue, May 15, 2012 at 8:56 PM, fc lists <fclists at pr-z.info> wrote:
>
>> Hi,
>>
>> I am trying to hook up  a NexentaStor ISCSI server with opennebula 3.4.1
>>
>> I created a DS_MAD and TM_MAD out of the current "iscsi" ones and i got
>> everything working fine ... other then live migration.
>>
>> Things goes like this:
>>
>> Create New Virtual Machine
>>
>> oneadmin ssh to HOST1
>>  - login into ISCSI
>>  - LN the system datastore (NFS Shared) disk to the ISCSI device
>>
>> live migrate from HOST1 to HOST2
>>
>> At this point HOST 2 has no knowledge of ISCSI device ... because the FE
>> never performed ISCSI login on host2.
>>
>> "at first" i thought that the "MV" TM_MAD would be called for
>> live-migration the same way it get executed for cold migration, but it does
>> not seem so on my system.
>> Cold migration works just fine because it actively login the ISCSI target
>> in the HOST2 , with live-migration it seems like ONE does not really
>> interact with the cluster other then performing the libvirt/kvm live
>> migration.
>>
>> As a proof of concept it was enough to manually login the ISCSI target on
>> HOST2 and live-migration worked perfectly.
>>
>> Is there any hook that i can use to manage this operation ? Ideally it
>> would be enough to get the Image SOURCE available to get it to work.
>>
>> Thanks
>> -FC
>>
>> _______________________________________________
>> Users mailing list
>> Users at lists.opennebula.org
>> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>>
>>
>
>
> --
> Jaime Melis
> Project Engineer
> OpenNebula - The Open Source Toolkit for Cloud Computing
> www.OpenNebula.org | jmelis at opennebula.org
>
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