[libvirt-users] domain definition storage

[Daniel P. Berrange]

On Tue, Jan 26, 2010 at 09:51:00PM +0100, Arik Raffael Funke wrote:
> Hi Daniel,
> 
> >libvirt never directly stores its XML files when talking to Xen - it
> >always uses one of the two Xen formats as the master database instead.
> ...snipp...
> >On Xen>  3.0.3  libvirt uses the native Xen APIs, which result in the
> >files being stored in /var/lib/xend/domains instead.
> 
> So if I change the files in /var/lib/xend/domains manually, the changes 
> should stick, right? I tried that and occasionally the files revert to 
> the previous version.

No, XenD gets very unhappy if you change those files manually and will
freely overwrite your changes. 

> Could it be that the respective VM (or virt-manager?) must not be 
> running while changing the domain configuration files? Does libvirt or 
> xen store the domain configuration in memory while the machine/gui is 
> running and write it back to the configuration file when the machine/gui 
> shuts down?

If you want to update the guest config, you should always do it via the
libvirt APIs, or virsh tool,  eg  'virsh define GUEST.xml' or
'virsh edit GUESTNAME'. This ensures that XenD itself is always informed
of the changes.

Daniel
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