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Re: KVM Block Migration

 

Some consideration must be done.
First, supported qemu version. IMO,  Ubuntu maverick supported, natty … hopefully supported, but RHEL6 doesn’t.
If you would like to use not-Ubuntu environment, you need to check whether operating system supports or not.
Second, migrating qcow images. I tested maverick environment. Qcow image is usually shrinked  comparing with real image size. After block migration, image size is not shrinked. I’m not sure whether natty is fixed this.

If you would like to test under nova environment, quick solution is that :

1.     nova.scheduler.driver
comment out self._live_migration_common_check(….  at L101.


2.     add flag to  /etc/nova/nova-manage.conf
--live_migration_flag=”VIR_MIGRATE_UNDEFINE_SOURCE, …, VIR_MIGRATE_NON_SHARED_DISK”
(see nova.virt.libvirt_conn)


3.     Restart nova-compute ( both src and dst ), and scheduler



4.     Go live migaration

nova-manage vm live_migartion instance_id destination-host-name
Ideally, “nova-manage vm block_migration …” needs to be implemented, but not now.
it is going to be ready at Diablo-2 / Diablo-3 in our plan … do you want to work with us?
Actually, I am so glad someone is interested in this feature.

Masumotok


From: openstack-bounces+masumotok=nttdata.co.jp@xxxxxxxxxxxxxxxxxxx [mailto:openstack-bounces+masumotok=nttdata.co.jp@xxxxxxxxxxxxxxxxxxx] On Behalf Of Vishvananda Ishaya
Sent: Wednesday, May 11, 2011 3:58 AM
To: Mikhail Shcherbakov
Cc: openstack@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Openstack] KVM Block Migration

I don't know if anyone has started work on this feature.  Someone should file a blueprint.

Vish

On May 10, 2011, at 3:35 AM, Mikhail Shcherbakov wrote:


Hi,
Is there any progress on KVM block migration?

I'd like to test it and possibly make some changes to nova to support block devices,
but don't want to reinventing the wheel.

Thanks,

2011/4/12 Masanori ITOH <itoumsn@xxxxxxxxxxxxx<mailto:itoumsn@xxxxxxxxxxxxx>>

Hi,

Vish also mentioned that we should support the KVM block migration feature
instead of stability which I mentioned because it's very much useful.
I agree with Vish of course. :)
Actually, we discussed inclusion of block migration feature at San Antonio. :)


I've also seen the page Hisaki mentioned. My point is that
the page explains interacting qemu monitor but we need to invoke
the feature through libvirt layer not the qemu monitor directly.
Here, A colleague of mine mentioned that --copy-storage-all option of
virsh looked like not-supported yet in Ubuntu 10.10 at least.

Hisaki,
do you have any information if it's enabled in Ubuntu 11.04 libvirt?
I mean using virsh, did you succeed invoking block live migration
something like the following?

 $ virsh migrate --live --copy-storage-all DOMID DESTURL

Unfortunately, we haven't been able to make enough time trying Natty alpha
because of our schedule delay caused by the earthquake in Northeastern Japan. :(
At least, libvirt(virsh) included in RHEL6 does not support the feature.

But, anyway I will talk about the issue with Kei and Muneyuki before going to
the Design Summit. :)

Regards,
Masanori


From: igoigo246 <igoigo246@xxxxxxxxx<mailto:igoigo246@xxxxxxxxx>>
Subject: Re: [Openstack] KVM Block Migration
Date: Tue, 12 Apr 2011 09:28:38 +0900

> Hi,
>
> I look Japanease Site.
> http://www.cuspy.org/blog/archives/917
>
> This site wrote.
>
> image file
> vda.qcow
>
> sending host
>
> qemu --enable-kvm -m 512 \
> -drive file=vda.qcow,if=virtio,boot=on \
> -net nic,macaddr=00:16:3E:00:FF:32,model=virtio
>
> receive host
>
> touch vda.qcow
> qemu -enable-kvm -m 512 \
> -drive file=vda.qcow,if=virtio \
> -net nic,macaddr=00:16:3E:00:FF:32,model=virtio \
> -incoming tcp:0:4444
>
> sending host
>
> migrate -d -b tcp:wasabi:4444
>
>
> (qemu) info migrate
> Migration status: active
> transferred ram: 48 kbytes
> remaining ram: 147792 kbytes
> total ram: 147840 kbytes
> transferred disk: 206848 kbytes
> remaining disk: 10278912 kbytes
> total disk: 10485760 kbytes
>
> Thanks,
>
> --
> Hisashi Ikari
>
>
>
>
>
> 2011-04-11 (月) の 16:50 +0900 に Masanori ITOH さんは書きました:
> > Hi,
> >
> > We are considering if it's possible to support KVM block migration
> > as the next step of live migration.
> >
> > Actually, our main issue at this moment is if that kvm feature is enough
> > stable or not because we got several errors during our try of it
> > using Ubuntu 10.10 code base. Especially, I'm not sure if the feature
> > is enabled or not in the qemu-kvm bundled in Ubuntu/RHEL.
> >
> > Do you have any information about stability?
> >
> > Thanks,
> > Masanori
> >
> > ---
> > Masanori ITOH  R&D Headquarters, NTT DATA CORPORATION
> >                e-mail: itoumsn@xxxxxxxxxxxxx<mailto:itoumsn@xxxxxxxxxxxxx>
> >
> > From: igoigo246 <igoigo246@xxxxxxxxx<mailto:igoigo246@xxxxxxxxx>>
> > Subject: [Openstack] (no subject)
> > Date: Mon, 11 Apr 2011 14:41:20 +0900
> >
> > > hi all
> > >
> > > KVM Block Migration is wonderful function.
> > >
> > > http://www.linux-kvm.com/content/qemu-kvm-012-adds-block-migration-feature
> > >
> > > this allow   that live migration do  without shared storage.
> > >
> > >
> > > When KVM Block migration Support ?
> > >
> > >
> > > Thanks for reading.
> > > --
> > > Hisashi Ikari
> > >
> > >
> > > _______________________________________________
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>

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--
Mike Scherbakov
www.mirantis.com<http://www.mirantis.com/>
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