Actually, the machine running VM only has one user : root.
I login the machine and run ssh both with the root permission.
And I also have a  try by using "virt-viewer -c qemu+ssh://root@192.168.7.126/system vt_c_ubuntu"
It still shows the same message .

best regards,
qinguan


2011/5/5 Daniel P. Berrange <berrange@redhat.com>
On Thu, May 05, 2011 at 06:46:32PM +0800, guan qin wrote:
> yeh,it's working !
> I can see that the VM already running and never kill itself now.
> I appreciate your help very much.
>
> but I meet another problem after I upgrade the libvirt version from 0.8.3 to
> 0.9.0.
> I find that if I use "virt-viewer -c
> qemu+ssh://192.168.7.126/systemvt_d_ubuntu",
> the machine shows a message that "Unable to connect to libvirt with URL
> qemu+ssh://192.168.7.126/system ".

This is ssh'ing as an unprivileged user, and so it likely doesn't have
permission for the socket. You can try  'qemu+ssh://root@192.168.7.126/system'
instead

Also see these pages

 http://wiki.libvirt.org/page/Main_Page#SSH

Daniel
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