libvirt users - Apr 2016 - Re: Clone VM with saved state

Hi,

My use case involves creating duplicates of saved virtual machines.
Tried with virt-manager and with virsh but so far it seems like this case
is not supported by these tools.
Does anyone know how I could achieve the above?

Thanks,
Michael

On Mon, Apr 11, 2016 at 12:01:08PM +0300, Michael Ravits
wrote:
> Hi,
> 
> My use case involves creating duplicates of saved virtual machines.
While I realize you want to trivially clone VMs with some state at
random point in time, you might want to look into `virt-builder` about
cloning VMs.  It has some sensible advice:

    http://libguestfs.org/virt-builder.1.html#clones

Using `virt-builder` to clone images, will 'sysprep' the images, which
will ensure that (a) each VM copy gets a fresh pair of SSH host keys;
(b) a new random seed; (c) all security/sensitive information is
removed; (d) log files are cleaned (in the below URL, look up the string
"logfiles *" to see what all it removes), and much more.   Take a look
here for what all it does:

    http://libguestfs.org/virt-sysprep.1.html#operations
    http://libguestfs.org/virt-sysprep.1.html#security  
> Tried with virt-manager and with virsh but so far it seems like this
> case is not supported by these tools.  Does anyone know how I could
> achieve the above?
With 'virsh', you _can_ save the live disk and memory state:

    $ virsh snapshot-create-as \
        --domain myvm snap1 \
        --diskspec vda,file=./disk-snap.qcow2,snapshot=external \
        --memspec file=./mem-snap.qcow2,snapshot=external \
        --atomic


-- 
/kashyap

Hi Kashyap,

Thanks for your answer!

Unfortunately my use case requires cloning the exact memory state, so I
won't be able to use virt-sysprep.
But the snapshot command looks like something I could use.
Could you suggest how to proceed and create/start a new vm from that
snapshot?

Thanks,
Michael

On Tue, Apr 12, 2016 at 2:37 PM, Kashyap Chamarthy <kchamart@redhat.com>
wrote:
> On Mon, Apr 11, 2016 at 12:01:08PM +0300, Michael Ravits wrote:
> > Hi,
> >
> > My use case involves creating duplicates of saved virtual machines.
>
> While I realize you want to trivially clone VMs with some state at
> random point in time, you might want to look into `virt-builder` about
> cloning VMs.  It has some sensible advice:
>
>     http://libguestfs.org/virt-builder.1.html#clones
>
> Using `virt-builder` to clone images, will 'sysprep' the images,
which
> will ensure that (a) each VM copy gets a fresh pair of SSH host keys;
> (b) a new random seed; (c) all security/sensitive information is
> removed; (d) log files are cleaned (in the below URL, look up the string
> "logfiles *" to see what all it removes), and much more.   Take a
look
> here for what all it does:
>
>     http://libguestfs.org/virt-sysprep.1.html#operations
>     http://libguestfs.org/virt-sysprep.1.html#security
>
> > Tried with virt-manager and with virsh but so far it seems like this
> > case is not supported by these tools.  Does anyone know how I could
> > achieve the above?
>
> With 'virsh', you _can_ save the live disk and memory state:
>
>     $ virsh snapshot-create-as \
>         --domain myvm snap1 \
>         --diskspec vda,file=./disk-snap.qcow2,snapshot=external \
>         --memspec file=./mem-snap.qcow2,snapshot=external \
>         --atomic
>
>
> --
> /kashyap
>