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Hi!

Actually, I have already filed cancel of LiveMigration with using taskflow
[0].
But my approach to blueprint was not so good at that time.
So, I rewrote this blueprint from also point of russelb.
I want to repush and wanted to approved.

If you have any suggestions, ideas etc...
I appreciate it :)

Sincerely, Haruka Tanizawa


[0] https://blueprints.launchpad.net/nova/+spec/feature-of-cancel


2013/12/17 Yaguang Tang <yaguang.tang at canonical.com>

> could we use Taskflow <https://wiki.openstack.org/wiki/TaskFlow> to
> manage task state and resource for this kind of tasks in Nova? Cinder has
> been an pilot to use Taskflow for volume backup tasks. anyone interested in
> this suggestion or has done some research to improve the live migration
> workflow?
>
>
> 2013/12/17 Vladik Romanovsky <vladik.romanovsky at enovance.com>
>
>> I would block it in the API or have the API cancelling the migration
>> first.
>> I don't see a reason why to start an operation that is meant to fail,
>> which also has a complex chain of event, following it failure.
>>
>> Regardless of the above, I think that the suggested exception handling is
>> needed in any case.
>>
>>
>> Vladik
>>
>> ----- Original Message -----
>> > From: "Loganathan Parthipan" <parthipan at hp.com>
>> > To: "OpenStack Development Mailing List (not for usage questions)" <
>> openstack-dev at lists.openstack.org>
>> > Sent: Monday, 16 December, 2013 8:25:09 AM
>> > Subject: Re: [openstack-dev] [Nova][libvirt]when deleting instance
>> which is in migrating state, instance files can be
>> > stay in destination node forever
>> >
>> >
>> >
>> > Isn’t just handling the exception instance_not_found enough? By this
>> time
>> > source would’ve been cleaned up. Destination VM resources will get
>> cleaned
>> > up by the periodic task since the VM is not associated with this host.
>> Am I
>> > missing something here?
>> >
>> >
>> >
>> >
>> >
>> >
>> > From: 王宏 [mailto:w.wanghong1 at gmail.com]
>> > Sent: 16 December 2013 11:32
>> > To: openstack-dev at lists.openstack.org
>> > Subject: [openstack-dev] [Nova][libvirt]when deleting instance which is
>> in
>> > migrating state, instance files can be stay in destination node forever
>> >
>> >
>> >
>> >
>> >
>> > Hi all.
>> >
>> >
>> > When I try to fix a bug: https://bugs.launchpad.net/nova/+bug/1242961 ,
>> >
>> >
>> > I get a trouble.
>> >
>> >
>> >
>> >
>> >
>> > To reproduce the bug is very easy. Live migrate a vm in block_migration
>> mode,
>> >
>> >
>> > and then delelte the vm immediately.
>> >
>> >
>> >
>> >
>> >
>> > The reason of this bug is as follow:
>> >
>> >
>> > 1. Because live migrate costs more time, so the vm will be deleted
>> > sucessfully
>> >
>> >
>> > before live migrate complete. And then, we will get an exception while
>> live
>> >
>> >
>> > migrating.
>> >
>> >
>> > 2. After live migrate failed, we start to rollback. But, in the rollback
>> > method
>> >
>> >
>> > we will get or modify the info of vm from db. Because the vm has been
>> deleted
>> >
>> >
>> > already, so we will get instance_not_found exception and rollback will
>> be
>> >
>> >
>> > faild too.
>> >
>> >
>> >
>> >
>> >
>> > I have two ways to fix the bug:
>> >
>> >
>> > i)Add check in nova-api. When try to delete a vm, we return an error
>> message
>> > if
>> >
>> >
>> > the vm_state is LIVE_MIGRATING. This way is very simple, but need to
>> > carefully
>> >
>> >
>> > consider. I have found a related discussion:
>> >
>> >
>> >
>> http://lists.openstack.org/pipermail/openstack-dev/2013-October/017454.html,
>> > but
>> >
>> >
>> > it has no result in the discussion.
>> >
>> >
>> > ii)Before live migrate we get all the data needed by rollback method,
>> and add
>> > a
>> >
>> >
>> > new rollback method. The new method will clean up resources at
>> destination
>> > based
>> >
>> >
>> > on the above data(The resouces at source has been already cleaned up by
>> >
>> >
>> > deleting).
>> >
>> >
>> >
>> >
>> >
>> > I have no idea whitch one I should choose. Or, any other ideas?:)
>> >
>> >
>> >
>> >
>> >
>> > Regards,
>> >
>> >
>> > wanghong
>> >
>> > _______________________________________________
>> > OpenStack-dev mailing list
>> > OpenStack-dev at lists.openstack.org
>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>> >
>>
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>>
>
>
>
> --
> Tang Yaguang
>
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