[Qemu-devel] How to clone a running vm?

[Qemu-devel] How to clone a running vm?

[Zhang Haoyu]

Hi,

I want to clone a running vm without shutoff,
can below method work?
1) create a snapshot for the vm
2) create a new qcow2 image from the snapshot, but how?
3) use the new qcow2 image as backing image to clone vms

Any ideas?

Thanks,
Zhang Haoyu
 

Re: [Qemu-devel] How to clone a running vm?

[Zhang Haoyu]

On 2015-01-12 15:50:13, Zhang Haoyu wrote:
>Hi,
>
>I want to clone a running vm without shutoff,
>can below method work?
>1) create a snapshot for the vm
>2) create a new qcow2 image from the snapshot, but how?
>3) use the new qcow2 image as backing image to clone vms
>
Can drive_mirror clone a running vm without guest service disruption?

>Any ideas?
>
>Thanks,
>Zhang Haoyu

Re: [Qemu-devel] How to clone a running vm?

[Paolo Bonzini]

On 12/01/2015 09:15, Zhang Haoyu wrote:
> > I want to clone a running vm without shutoff,
> > can below method work?
> > 1) create a snapshot for the vm
> > 2) create a new qcow2 image from the snapshot, but how?
> > 3) use the new qcow2 image as backing image to clone vms
>
> Can drive_mirror clone a running vm without guest service disruption?

Yes.

Paolo

Re: [Qemu-devel] How to clone a running vm?

[Eric Blake]

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On 01/12/2015 12:49 AM, Zhang Haoyu wrote:
> Hi,
> 
> I want to clone a running vm without shutoff,

A number of people have expressed a desire to do this. But PLEASE
consider the security implications.  If you have two guests running from
the same initial running state, without sanitizing at least one of the
guests, then you have set yourself up for major security breaches if the
two guests can be accessed on the same network.

Things you need to sanitize include, but are not limited to, all guest
OS random number seeding, IP addresses, UUIDs, ssh keys, etc.

> can below method work?
> 1) create a snapshot for the vm
> 2) create a new qcow2 image from the snapshot, but how?
> 3) use the new qcow2 image as backing image to clone vms

While you can indeed create a qcow2 image from a running guest, I highly
suggest scrubbing and sanitizing that image before cloning new VMs that
use that state; and that your new guests be booted from scratch rather
than attempting to live-boot the cloned guests.

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


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