Containers fail to start after server upgrade to Ubuntu 18.04.2 LTS

root@dev ~ # snap info lxd
name:      lxd
summary:   System container manager and API
publisher: Canonical✓
contact:   https://github.com/lxc/lxd/issues
license:   unset
description: |
  **LXD is a system container manager**

  With LXD you can run hundreds of containers of a variety of Linux
  distributions, apply resource limits, pass in directories, USB devices
  or GPUs and setup any network and storage you want.

  LXD containers are lightweight, secure by default and a great
  alternative to running Linux virtual machines.


  **Run any Linux distribution you want**

  Pre-made images are available for Ubuntu, Alpine Linux, ArchLinux,
  CentOS, Debian, Fedora, Gentoo, OpenSUSE and more.

  A full list of available images can be [found here](https://images.linuxcontainers.org)

  Can't find the distribution you want? It's easy to make your own images too, either using our
  `distrobuilder` tool or by assembling your own image tarball by hand.


  **Containers at scale**

  LXD is network aware and all interactions go through a simple REST API,
  making it possible to remotely interact with containers on remote
  systems, copying and moving them as you wish.

  Want to go big? LXD also has built-in clustering support,
  letting you turn dozens of servers into one big LXD server.


  **Configuration options**

  Supported options for the LXD snap (`snap set lxd KEY=VALUE`):
   - criu.enable: Enable experimental live-migration support [default=false]
   - daemon.debug: Increases logging to debug level [default=false]
   - daemon.group: Group of users that can interact with LXD [default=lxd]
   - ceph.builtin: Use snap-specific ceph configuration [default=false]
   - openvswitch.builtin: Run a snap-specific OVS daemon [default=false]

  [Documentation](https://lxd.readthedocs.io)
snap-id:      J60k4JY0HppjwOjW8dZdYc8obXKxujRu
tracking:     stable
refresh-date: yesterday at 22:46 CET
channels:
  stable:        3.10        2019-02-25 (10234) 54MB -
  candidate:     3.10        2019-02-25 (10234) 54MB -
  beta:          ↑
  edge:          git-0d70553 2019-02-26 (10250) 54MB -
  3.0/stable:    3.0.3       2018-11-26  (9663) 53MB -
  3.0/candidate: 3.0.3       2019-01-19  (9942) 53MB -
  3.0/beta:      ↑
  3.0/edge:      git-eaa62ce 2019-02-19 (10212) 53MB -
  2.0/stable:    2.0.11      2018-07-30  (8023) 28MB -
  2.0/candidate: 2.0.11      2018-07-27  (8023) 28MB -
  2.0/beta:      ↑
  2.0/edge:      git-c7c4cc8 2018-10-19  (9257) 26MB -
installed:       3.10                   (10234) 54MB -