I've started noticing a lot of these in the neutron job logs:
http://logs.openstack.org/67/269867/4/check/gate-tempest-dsvm-neutron-src-os-brick/7617a9f/logs/screen-n-cpu.txt.gz#_2016-01-21_05_38_48_667
2016-01-21 05:38:48.667 ERROR nova.virt.libvirt.driver [req-c8971f87-303e-460b-894b-7e2ccde9944f nova service] [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] detaching network adapter failed.
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] Traceback (most recent call last):
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/opt/stack/new/nova/nova/virt/libvirt/driver.py", line 1354, in detach_interface
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] guest.detach_device(cfg, persistent=True, live=live)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/opt/stack/new/nova/nova/virt/libvirt/guest.py", line 341, in detach_device
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] self._domain.detachDeviceFlags(conf.to_xml(), flags=flags)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 183, in doit
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] result = proxy_call(self._autowrap, f, *args, **kwargs)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 141, in proxy_call
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] rv = execute(f, *args, **kwargs)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 122, in execute
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] six.reraise(c, e, tb)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/usr/local/lib/python2.7/dist-packages/eventlet/tpool.py", line 80, in tworker
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] rv = meth(*args, **kwargs)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] File "/usr/local/lib/python2.7/dist-packages/libvirt.py", line 985, in detachDeviceFlags
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] if ret == -1: raise libvirtError ('virDomainDetachDeviceFlags() failed', dom=self)
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d] libvirtError: operation failed: no matching network device was found
2016-01-21 05:38:48.667 12834 ERROR nova.virt.libvirt.driver [instance: d8d15c87-79cc-4b63-99bb-64dde4576b3d]
Following the request ID, it's coming from a neutron vif deleted event:
http://logs.openstack.org/67/269867/4/check/gate-tempest-dsvm-neutron-src-os-brick/7617a9f/logs/screen-n-cpu.txt.gz#_2016-01-21_05_38_48_361
It looks like we should just handle and not log that network device not found as an error, but libvirt doesn't provide a specific error code for that case:
http://libvirt.org/git/?p=libvirt.git;a=blob;f=src/qemu/qemu_driver.c;h=e04a32841807851fd1386ab8a7fd91672f114dce;hb=e8684eb541f01df9b45e87e0a8ce446c7bc90a17#l6764
And the error message is translatable so we can't just parse the message either.
It seems there should be a way to verify that the network device exists before we try to detach it from the config so we can avoid this error which doesn't actually result in job failures (it's probably happening during an instance delete asynchronously where we're deleting the ports in neutron).
http://logstash.openstack.org/#dashboard/file/logstash.json?query=message%3A%5C%22Caught%20error%3A%20%3Ctype%20'exceptions.AttributeError'%3E%20'module'%20object%20has%20no%20attribute%20'ServiceList'%5C%22%20AND%20tags%3A%5C%22screen-c-api.txt%5C%22&from=7d
> It seems there should be a way to verify that the network device exists
You can query the guest XML to see if it exists as that should reflect current state