ERROR juju.provisioner provisioner_task.go:707 cannot start instance for machine "": unexpected number of interfaces in response from creating device

[Tytus Kurek]

With Juju 2.1.2 LXD containers sometimes fail to create with the following error message:

2017-05-15 09:10:38 WARNING juju.provisioner provisioner_task.go:739 failed to start instance (Error calling 'lxd forkstart juju-5bc85b-2-lxd-5 /var/lib/lxd/containers /var/log/lxd/juju-5bc85b-2-lxd-5/lxc.conf': err='exit status 1'
  lxc 20170515091031.423 ERROR lxc_conf - conf.c:run_buffer:405 - Script exited with status 1.
  lxc 20170515091031.423 ERROR lxc_start - start.c:lxc_init:450 - Failed to run lxc.hook.pre-start for container "juju-5bc85b-2-lxd-5".
  lxc 20170515091031.423 ERROR lxc_start - start.c:__lxc_start:1302 - Failed to initialize container "juju-5bc85b-2-lxd-5".
), retrying in 10s (3 more attempts)
2017-05-15 09:10:49 WARNING juju.provisioner provisioner_task.go:739 failed to start instance (unexpected number of interfaces in response from creating device: [0xc82343bad0 0xc82343bba0 0xc82343bc70 0xc82343bd40 0xc82343be10]), retrying in 10s (2 more attempts)
2017-05-15 09:11:01 WARNING juju.provisioner provisioner_task.go:739 failed to start instance (unexpected number of interfaces in response from creating device: [0xc8254b4b60 0xc8254b4c30 0xc8254b4d00 0xc8254b4ea0 0xc8254b4f70]), retrying in 10s (1 more attempts)
2017-05-15 09:11:12 ERROR juju.provisioner provisioner_task.go:707 cannot start instance for machine "2/lxd/5": unexpected number of interfaces in response from creating device: [0xc82271d110 0xc82271d1e0 0xc82271d2b0 0xc82271d380 0xc82271d450]

The issue has already been mentioned here: https://bugs.launchpad.net/juju/+bug/1681902

[John A Meinel (jameinel)]

This has already been fixed in 2.2.