Open Stack

2014/1/8 John Garbutt <john at johngarbutt.com>

> On 8 January 2014 10:02, David Xie <david.scriptfan at gmail.com> wrote:
> > In nova/compute/api.py#2289, function resize, there's a parameter named
> > flavor_id, if it is None, it is considered as cold migration. Thus, nova
> > should skip resize verifying. However, it doesn't.
> >
> > Like Jay said, we should skip this step during cold migration, does it
> make
> > sense?
>
> Not sure.
>
> > On Wed, Jan 8, 2014 at 5:52 PM, Jay Lau <jay.lau.513 at gmail.com> wrote:
> >>
> >> Greetings,
> >>
> >> I have a question related to cold migration.
> >>
> >> Now in OpenStack nova, we support live migration, cold migration and
> >> resize.
> >>
> >> For live migration, we do not need to confirm after live migration
> >> finished.
> >>
> >> For resize, we need to confirm, as we want to give end user an
> opportunity
> >> to rollback.
> >>
> >> The problem is cold migration, because cold migration and resize share
> >> same code path, so once I submit a cold migration request and after the
> cold
> >> migration finished, the VM will goes to verify_resize state, and I need
> to
> >> confirm resize. I felt a bit confused by this, why do I need to verify
> >> resize for a cold migration operation? Why not reset the VM to original
> >> state directly after cold migration?
>
> I think the idea was allow users/admins to check everything went OK,
> and only delete the original VM when the have confirmed the move went
> OK.
>
> I thought there was an auto_confirm setting. Maybe you want
> auto_confirm cold migrate, but not auto_confirm resize?
>






*[Jay] John, yes, that can also reach my goal. Now we only have
resize_confirm_window to handle auto confirm without considering it is
resize or cold migration. # Automatically confirm resizes after N seconds.
Set to 0 to# disable. (integer value)#resize_confirm_window=0 *
*Perhaps we can add another parameter say cold_migrate_confirm_window to
handle confirm for cold migration.*

>
> >> Also, I think that probably we need split compute.api.resize() to two
> >> apis: one is for resize and the other is for cold migrations.
> >>
> >> 1) The VM state can be either ACTIVE and STOPPED for a resize operation
> >> 2) The VM state must be STOPPED for a cold migrate operation.
>
> We just stop the VM them perform the migration.
> I don't think we need to require its stopped first.
> Am I missing something?
>
*[Jay] Yes, but just curious why someone want to cold migrate an ACTIVE VM?
They can use live migration instead and this can also make sure the VM
migrate seamlessly.*

>
> Thanks,
> John
>
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