Traceback (most recent call last):
  File "/etc/munin/plugins/libvirt", line 44, in <module>
    conn = libvirt.openReadOnly(uri)
  File "/usr/lib/python2.6/dist-packages/libvirt.py", line 180, in openReadOnly
    if ret is None:raise libvirtError('virConnectOpenReadOnly() failed')
libvirtError: unable to connect to '/var/run/libvirt/libvirt-sock-ro': No such file or directory