[Gllug] Xen Control Stuff

[Daniel P. Berrange]

On Sun, Jul 22, 2007 at 03:27:52PM +0100, Ian Norton-Badrul wrote:
> On Tue, Jul 17, 2007 at 05:16:36PM +0100, Daniel P. Berrange wrote:
> > On Tue, Jul 17, 2007 at 10:31:32PM +0100, Ian Norton-Badrul wrote:
> > > On Mon, Jul 16, 2007 at 04:30:13PM +0100, Richard Jones wrote:
> > > > 
> > > > Dan's already given you the libvirt spiel.  I took a look at Dupe, and
> > > > since it's written in Perl you'll be interested in the Perl bindings
> > > > for libvirt:
> > > > 
> > > > http://search.cpan.org/~danberr/Sys-Virt-0.1.1/lib/Sys/Virt.pm
> > > > 
> > > > You'll appreciate libvirt if at some point you decide that Xen isn't
> > > > quite the way of the future, and something integrated into the Linux
> > > > kernel like KVM or lguest is better.  Not that that would ever happen.
> > > > Oh no.
> > > 
> > > I agree, libvirt is a fairly good bet, however I did find that the perl binding
> > > were a tad slow, and plus I have found that alot of the xen xml-rpc calls
> > > changed between xen 3.0 and 3.1, so presumably i'd be waiting for libvirt to
> > > catch-up before dupe could.
> > 
> > We supported Xen 3.1 from pretty much the day it came out. We avoid
> > the XML-RPC api currently since its was constantly changing. We use
> > either direct hypercalls (x1000 faster than talking to XenD) whereever
> > possible, only falling back to talking to XenD HTTP service if we have
> > no other choice. XenD+XenStoreD are hugely non-scalable for performance
> > unfortunately :-(
> > 
> > > I'll probably re-visit libvirt for perl soon (just as soon as I sort out the
> > > problem where I can only boot my xen machine with once pci card).
> > 
> > Let me know if there's specific issues with the Perl bindings - they
> > should be a straight passthrough to the C api, so any speed issues
> > are in the underlying code. Most likely I reckon you tried to use
> > them as non-root, which would mean it had to talk to XenD instead of
> > the hypervisor. In the libvirt from a couple of weeks ago we have
> > full 'remote management' letting libvirt securely work as non-root
> > both on & off the box - this is again several orders of magnitude
> > faster than talking to XenD, so may be of use. 
> 
> That sounds extreemly cool! Can I ask, does libvirt provide any interface for
> managment of device backends? (disks, lvm etc) 

Not at this time, but its one of the items on our roadmap, since its
obviously critical if you want to be able to create new virtual 
machines from a remote host without the admin pre-initializing the
storage.

Regards,
Dan.
-- 
|=-            GPG key: http://www.berrange.com/~dan/gpgkey.txt       -=|
|=-       Perl modules: http://search.cpan.org/~danberr/              -=|
|=-           Projects: http://freshmeat.net/~danielpb/               -=|
|=-   berrange at redhat.com  -  Daniel Berrange  -  dan at berrange.com    -=|
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