This seems to be a problem again:

  $ juju version
  2.0-beta12-xenial-amd64


$ juju version
2.0-beta12-xenial-amd64
aim@spicy:~/kvm-maas (master) 
$ juju show-machines 2
model: controller
machines:
  "2":
    juju-status:
      current: started
      since: 14 Jul 2016 12:28:20+01:00
      version: 2.0-beta12.1
    dns-name: 10.11.19.122
    instance-id: /MAAS/api/1.0/nodes/node-4447f4fc-49b5-11e6-8b89-525400b0e64b/
    machine-status:
      current: running
      message: Deployed
      since: 14 Jul 2016 12:27:48+01:00
    series: trusty

ubuntu@maas19-node6:~$ cat /etc/cloud/build.info 
build_name: server
serial: 20160411

ubuntu@maas19-node6:~$ cat /etc/apt/sources.list
deb http://archive.ubuntu.com//ubuntu  trusty main restricted universe multiverse
deb http://archive.ubuntu.com//ubuntu  trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com//ubuntu  trusty-security main restricted universe multiverse

ubuntu@maas19-node6:~$ cat /etc/apt/sources.list
deb http://archive.ubuntu.com//ubuntu  trusty main restricted universe multiverse
deb http://archive.ubuntu.com//ubuntu  trusty-updates main restricted universe multiverse
deb http://archive.ubuntu.com//ubuntu  trusty-security main restricted universe multiverse
ubuntu@maas19-node6:~$ sudo grep backports /var/log/juju/machine-2.log 
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:57 Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:33:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:33:56 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:06 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:16 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:26 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:34:56 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:06 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:16 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:26 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:35:56 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:06 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:16 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:26 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:36:56 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:06 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:16 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:26 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:37:56 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:06 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:16 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:26 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:26 ERROR juju.utils.packaging.manager utils.go:103 packaging command failed: exit status 100; cmd: "apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd"; output: Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:29 INFO juju.utils.packaging.manager utils.go:57 Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd
2016-07-14 11:38:29 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:39 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:49 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:38:59 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:09 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:19 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:29 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:39 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:49 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:39:59 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:09 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:19 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:29 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:39 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:49 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:40:59 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:09 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:19 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:29 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:39 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:49 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:41:59 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:42:09 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:42:19 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:42:29 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
ubuntu@maas19-node6:~$ 
ubuntu@maas19-node6:~$ 
ubuntu@maas19-node6:~$ sudo grep backports /var/log/juju/machine-2.log  |head -5
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:57 Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:33:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
ubuntu@maas19-node6:~$ 
ubuntu@maas19-node6:~$ sudo grep backports /var/log/juju/machine-2.log  |head -5
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:57 Running: apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd
2016-07-14 11:33:36 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
E: The value 'trusty-backports' is invalid for APT::Default-Release as such a release is not available in the sources
2016-07-14 11:33:46 INFO juju.utils.packaging.manager utils.go:98 Retrying: &{/usr/bin/apt-get [apt-get --option=Dpkg::Options::=--force-confold --option=Dpkg::options::=--force-unsafe-io --assume-yes --quiet install --target-release trusty-backports lxd] []  <nil> Reading package lists...