[libvirt] [RFC] Unify KVM kernel-space and user-space code into a single project

Daniel Veillard veillard at redhat.com
Fri Apr 9 07:49:51 UTC 2010

On Thu, Apr 08, 2010 at 11:27:46PM +0100, Antoine Martin wrote:
> Hi,
> I am moving this thread here as this seems more appropriate.
> Sorry it has taken so long..
> Here are 2 things that really get in the way of moving my existing
> installations to libvirt:
> * I tend to store much meta data with each VM instance: it can be things
> like ownership (contact details as text), monitoring info (sms phone
> numbers), backup (list of paths), firewall rules (custom syntax, with
> failover rules, etc), etc.
> At the moment, these extra bits of information consist of just a few
> optional lines of shell in each VM's definition file. I can extend these
> whenever I need, enumerate the VMs using the standard mechanism and
> trigger my specific actions as needed (firewall rules, backup or whatever).
> I see no way of doing this with libvirt. But please correct me if I am
> wrong.

  One of the things I'm gonna do post 0.8.0 is allow to bundle comments
and elements from a foreign namespace in the libvirt XML definition.

  Currently libvirt will happilly consume such a definition but all the
extra are lost, basically at parse time we just extract the informations
we know about, and everything else is lost. I want to provide clean ways
to add metadata coming from the user and preserve them. I will probably
limit the places where such metadata will be allowed:

  1/ to avoid the full complexity of an XML structured editor within
  2/ to not have to completely modify our configuration reading and
     saving code, but add this as an extra layer
  3/ to be able to modify the Relax-NG schemas in a reasonnable way
     to allow those elements from foreign namespaces

  It's not a piece of cake, there will have to be some limitation and
heuristics to avoid the extreme complexity and changes that a full tree
preservation system would requires, but I think that should be
sufficient for your kind of use case,


Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel at veillard.com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/

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