libvirt users - Sep 2015 - Re: about guest live migration configuration changes persistence ..

Hi,


Is a change , by edit it via virsh edit  , in the "local" .xml
configuration file (i.e. adding a channel device)  persistent when
live migrating the guest on another host ?

Thx.


J.P. Ribeauville


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On 31.08.2015 09:27, Jean-Pierre Ribeauville wrote:
> Hi,
> 
> 
> Is a change , by edit it via virsh edit  , in the "local" .xml
configuration file (i.e. adding a channel device)  persistent when
> live migrating the guest on another host ?
Yes. Since the 0.9.7 release, the configuration XML is transferred to
the other side too. However, by default, migrated domains are just
transient (unless you pass VIR_MIGRATE_PERSIST_DEST flag, or virsh
migrate --persistent ..) so the configuration XML doesn't have much
effect in that case.

Michal

Hi,

Thanks for infos.

My concern is the following :

In order to establish datas exchanges between hosts and guest , I'll add a
channel device to a running Guest ( as I learned from you  that it's 
possible to do that without stopping the Guest).
When the guest migrates to another host , this one must be able to retrieve the
channel device parameters to be able to dialog with the migrated guest.
I plan to use dumpxml to retrieve these  infos.
Will these infos be updated on the second host where  the guest has migrated ?

Thx.

J.P.

-----Message d'origine-----
De : Michal Privoznik [mailto:mprivozn@redhat.com] 
Envoyé : mercredi 2 septembre 2015 14:12
À : Jean-Pierre Ribeauville; libvirt-users@redhat.com
Objet : Re: [libvirt-users] about guest live migration configuration changes
persistence ..

On 31.08.2015 09:27, Jean-Pierre Ribeauville wrote:
> Hi,
> 
> 
> Is a change , by edit it via virsh edit  , in the "local" .xml 
> configuration file (i.e. adding a channel device)  persistent when live
migrating the guest on another host ?
Yes. Since the 0.9.7 release, the configuration XML is transferred to the other
side too. However, by default, migrated domains are just transient (unless you
pass VIR_MIGRATE_PERSIST_DEST flag, or virsh migrate --persistent ..) so the
configuration XML doesn't have much effect in that case.

Michal

On Wed, Sep 02, 2015 at 02:11:58PM +0200, Michal Privoznik
wrote:
> On 31.08.2015 09:27, Jean-Pierre Ribeauville wrote:
> > Hi,
> > 
> > 
> > Is a change , by edit it via virsh edit  , in the "local"
.xml configuration file (i.e. adding a channel device)  persistent when
> > live migrating the guest on another host ?
> 
> Yes. Since the 0.9.7 release, the configuration XML is transferred to
> the other side too. However, by default, migrated domains are just
> transient (unless you pass VIR_MIGRATE_PERSIST_DEST flag, or virsh
> migrate --persistent ..) so the configuration XML doesn't have much
> effect in that case.
For more info on the config file handling see:

  http://libvirt.org/migration.html#config

Regards,
Daniel
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