CI fixes/workarounds

[Danilo Šegan]

Hi all,

It seems MAAS CI has started failing recently with the following:

failed to create tun device: Operation not permitted
qemu-system-x86_64:/home/ubuntu/workspace/maas-xenial-trunk/maas-ci-config/etc/region.cfg:3: bridge helper failed
autopkgtest-virt-qemu: DBG: cleanup...
<VirtSubproc>: failure: Timed out waiting for /tmp/autopkgtest-virt-qemu.hekftn7o/ttyS0 socket

See eg.

http://162.213.35.104:8080/job/maas-xenial-trunk/1216/console
http://162.213.35.104:8080/job/maas-xenial-trunk-manual-juju/262/console
http://162.213.35.104:8080/job/arm64_firmware_update/32/console


region.cfg referenced above on our HP-DL360-Gen9 slave 
(http://162.213.35.104:8080/computer/HP-DL360-Gen9/) is the following:

----- 8< ----------- 8< -----
# qemu config file

[net]
  type = "bridge"
  vlan = "3"
  br = "br2"
  helper = "/usr/lib/qemu-bridge-helper"

[net]
  type = "nic"
  model = "virtio"
  macaddr = "DE:AD:BE:EF:6B:B3"
  vlan = "3"
----- 8< ----------- 8< -----

(pulled from maas-ci-config branch, where it has not changed since January 2017).


I've so far worked-around it by setting suid bit on /usr/lib/qemu/qemu-
bridge-helper (the above is just a symlink to this), and the following
job went past that on to running tests:

  http://162.213.35.104:8080/job/maas-xenial-trunk/1217/console

I am looking into why apparmor configuration from libvirt-bin package
is not working in this case so I can drop the workaround and fix it
properly.

Cheers,
Danilo