[Qemu-devel] Network Migration in QEMU during Live Migration

[Qemu-devel] Network Migration in QEMU during Live Migration

[Azizul Hakim]

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Hi all,

Does QEMU support network migration so that the migration process is
transparent to users? For example if my VM has a web server, I would like
my user still be able to send request to the server after the migration
process is completed. But since migration causes a change of the physical
machine, the IP address is different. So how do I achieve this? I
understand that I've to create bridge network. What other things do I've to
take care off? Is it possible at all?


Thanks
Azizul

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Re: [Qemu-devel] Network Migration in QEMU during Live Migration

[Eric Blake]

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On 02/04/2015 12:01 PM, Azizul Hakim wrote:
> Hi all,
> 
> Does QEMU support network migration so that the migration process is
> transparent to users? For example if my VM has a web server, I would like
> my user still be able to send request to the server after the migration
> process is completed. But since migration causes a change of the physical
> machine, the IP address is different. So how do I achieve this? I
> understand that I've to create bridge network. What other things do I've to
> take care off? Is it possible at all?

The IP address of the host is different, but the IP address seen by the
guest is the same.  Live migration has been possible for several years
with qemu, and people do it all the time.  The guest sees very minimal
downtime (a few milliseconds).  If you use a higher-layer software, like
libvirt, then triggering a live migration of a guest is quite easy.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] Network Migration in QEMU during Live Migration

[Gary R Hook]

On 2/4/15 2:02 PM, Eric Blake wrote:
> On 02/04/2015 12:01 PM, Azizul Hakim wrote:
>> Does QEMU support network migration so that the migration process is
>> transparent to users? For example if my VM has a web server, I would like
>> my user still be able to send request to the server after the migration
>> process is completed. But since migration causes a change of the physical
>> machine, the IP address is different. So how do I achieve this? I
>> understand that I've to create bridge network. What other things do I've to
>> take care off? Is it possible at all?
>
> The IP address of the host is different, but the IP address seen by the
> guest is the same.  Live migration has been possible for several years
> with qemu, and people do it all the time.  The guest sees very minimal
> downtime (a few milliseconds).  If you use a higher-layer software, like
> libvirt, then triggering a live migration of a guest is quite easy.

What he said. The guest doesn't know, doesn't care, and doesn't change 
its network configuration; external connections are maintained. Only the 
host upon which the guest runs changes, and that is kind of irrelevant 
from a guest perspective.

-- 
Gary R Hook
Senior Kernel Engineer
NIMBOXX, Inc