--- issues: - | When generating Libvirt XML to attach network interfaces for the `tap`, `ivs`, `iovisor`, `midonet`, and `vrouter` virtual interface types Nova previously generated an empty path attribute to the script element (`<script path=''/>`) of the interface. As of Libvirt 1.3.3 (`commit`_) and later Libvirt no longer accepts an empty path attribute to the script element of the interface. Notably this includes Libvirt 2.0.0 as provided with RHEL 7.3 and CentOS 7.3-1611. The creation of virtual machines with offending interface definitions on a host with Libvirt 1.3.3 or later will result in an error "libvirtError: Cannot find '' in path: No such file or directory". Additionally, where virtual machines already exist that were created using earlier versions of Libvirt interactions with these virtual machines via Nova or other utilities (e.g. `virsh`) may result in similar errors. To mitigate this issue Nova no longer generates an empty path attribute to the script element when defining an interface. This resolves the issue with regards to virtual machine creation. To resolve the issue with regards to existing virtual machines a change to Libvirt is required, this is being tracked in `Bugzilla 1412834`_ .. _commit: https://libvirt.org/git/?p=libvirt.git;a=commit;h=9c17d665fdc5f0ab74500a14c30627014c11b2c0 .. _Bugzilla 1412834: https://bugzilla.redhat.com/show_bug.cgi?id=1412834