[Libvir] trouble using ssh tunnel for remote hypervisor

[Guillaume Rousse <Guillaume Rousse inria fr>]

Hello.

I'm trying to use ssh tunnel for remote hypervisor access. However, I'm
can't make it working...

[guillaume oberkampf ~]$ LC_ALL=C virsh --connect
xen+ssh://root acacia futurs inria fr list --all
libvir: error : could not connect to xen://
error: failed to connect to the hypervisor
error: no valid connection

On the remote host:
[root acacia ~]# libvirtd --verbose
libvir: error : could not connect to xen://

It seems the error lies between libvirtd and the local hypervisor. And
indeed, local usage of virsh with xen:// URLs fail:
[root acacia ~]# LC_ALL=C virsh -c xen:// list
libvir: error : could not connect to xen://
error: failed to connect to the hypervisor
error: no valid connection

Using xen:///, instead of xen://, as explained at
http://libvirt.org/uri.html, is OK, despite a few error messages:
[root acacia ~]# LC_ALL=C virsh -c xen:/// list
libvir: Remote error : No such file or directory
libvir: warning : Failed to find the network: Is the daemon running ?
 Id Name                 State
----------------------------------
  0 Domain-0             running
  1 barman               blocked
  2 cocktail             blocked
  3 mojito               blocked

>From the documentation, it seems xen:// transport implies TLS, and
requires an host name, so it is quite normal it fails here (I didn't
generated any certificate). But how can I force libvirtd to use xen:///
transport then ? I don't see anything related in libvirt configuration
documentation at http://libvirt.org/remote.html ? Neither about how to
configure it for listening on unix transport, as explained in svn+ssh
transport requirements on the same page (but I presume it is the default) ?

Also, from where does those error and warning come ?
[root acacia ~]# LC_ALL=C virsh -c xen:/// list
libvir: Remote error : No such file or directory
libvir: warning : Failed to find the network: Is the daemon running ?
[..]

I'm using libvirt 0.3.2 on mandriva 2007.1, with xen 3.1.0.
-- 
Guillaume Rousse
Moyens Informatiques - INRIA Futurs
Tel: 01 69 35 69 62