Comment 0 for bug 1692028

Whilst testing the changes for nova-lxd to resolve issues with use of config-drive, I tripped over this issue; specifically the networking on a config-drive configured LXD instance never starts due to a duplicate MAC address on the lo and greptap0 devices.

Cloud-init v. 0.7.9 running 'init' at Fri, 19 May 2017 13:41:00 +0000. Up 2.0 seconds.
ci-info: ++++++++++++++++++++++++++++++++++++++++++++++++++++Net device info+++++++++++++++++++++++++++++++++++++++++++++++++++++
ci-info: +---------+-------+------------------------------+-----------+-------+-------------------------------------------------+
ci-info: | Device | Up | Address | Mask | Scope | Hw-Address |
ci-info: +---------+-------+------------------------------+-----------+-------+-------------------------------------------------+
ci-info: | gretap0 | False | . | . | . | 00:00:00:00:00:00 |
ci-info: | eth0 | True | . | . | . | fa:16:3e:1d:aa:ac |
ci-info: | eth0 | True | fe80::f816:3eff:fe1d:aaac/64 | . | link | fa:16:3e:1d:aa:ac |
ci-info: | lo | True | 127.0.0.1 | 255.0.0.0 | . | . |
ci-info: | lo | True | ::1/128 | . | host | . |
ci-info: | gre0 | False | . | . | . | 00-00-00-00-31-36-3a-33-00-00-00-00-00-00-00-00 |
ci-info: +---------+-------+------------------------------+-----------+-------+-------------------------------------------------+
2017-05-19 13:41:01,017 - util.py[WARNING]: failed stage init
failed run of stage init
------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 647, in status_wrapper
    ret = functor(name, args)
  File "/usr/lib/python3/dist-packages/cloudinit/cmd/main.py", line 365, in main_init
    init.apply_network_config(bring_up=bool(mode != sources.DSMODE_LOCAL))
  File "/usr/lib/python3/dist-packages/cloudinit/stages.py", line 629, in apply_network_config
    netcfg, src = self._find_networking_config()
  File "/usr/lib/python3/dist-packages/cloudinit/stages.py", line 616, in _find_networking_config
    if self.datasource and hasattr(self.datasource, 'network_config'):
  File "/usr/lib/python3/dist-packages/cloudinit/sources/DataSourceConfigDrive.py", line 150, in network_config
    self.network_json, known_macs=self.known_macs)
  File "/usr/lib/python3/dist-packages/cloudinit/sources/helpers/openstack.py", line 638, in convert_net_json
    known_macs = net.get_interfaces_by_mac()
  File "/usr/lib/python3/dist-packages/cloudinit/net/__init__.py", line 403, in get_interfaces_by_mac
    (name, ret[mac], mac))
RuntimeError: duplicate mac found! both 'gretap0' and 'lo' have mac '00:00:00:00:00:00'
------------------------------------------------------------
Cloud-init v. 0.7.9 running 'modules:config' at Fri, 19 May 2017 13:41:02 +0000. Up 4.0 seconds.
Cloud-init v. 0.7.9 running 'modules:final' at Fri, 19 May 2017 13:41:04 +0000. Up 6.0 seconds.
Cloud-init v. 0.7.9 finished at Fri, 19 May 2017 13:41:04 +0000. Datasource DataSourceConfigDrive [net,ver=2][source=/config-drive]. Up 6.0 seconds