To rename a libvirt virtual maschine, do:

• Stop the VM with

  virsh stop vmname

• Edit /etc/libvirt/qemu/vmoldame.xml to vmnewname.xml and replace occurances of the name in vim with:

  :%s/altername/neuername/g

• In order to reread the configuration file libvirt-bin must be restartet (which does not affect running VMs):

  service libvirt-bin restart

  (there may be a more common way with virsh)

• If the VM uses a logical volume, that must be renamed with

  lvrename /dev/vgname/lvoldname /dev/vgname/lvnewname

• Start the renamed VM :)