This will come up again and more frequently now that the LXD package upgrade will do the deb->snap transition even when running in a container itself.

As Colin I run (and others might) privileged containers a lot using those extra privs: http://paste.ubuntu.com/p/bcVHRBTKyP/

I never had an issue as I didn't try to snap-in-lxd on my own, but the new package transition will trigger this.

Due to that the severity of this case increases a bit.


[...]
Preparing to unpack .../16-apache2-utils_2.4.34-1ubuntu2_amd64.deb ...
Unpacking apache2-utils (2.4.34-1ubuntu2) over (2.4.34-1ubuntu1) ...
Preparing to unpack .../17-lxd-client_1%3a0.4_all.deb ...
Unpacking lxd-client (1:0.4) over (3.0.2-0ubuntu3) ...
Setting up apparmor (2.12-4ubuntu8) ...
Installing new version of config file /etc/apparmor.d/abstractions/private-files ...
Installing new version of config file /etc/apparmor.d/abstractions/private-files-strict ...
Installing new version of config file /etc/apparmor.d/abstractions/ubuntu-browsers.d/user-files ...
Skipping profile in /etc/apparmor.d/disable: usr.sbin.rsyslogd
Setting up squashfs-tools (1:4.3-6ubuntu2) ...
Setting up libapparmor1:amd64 (2.12-4ubuntu8) ...
Setting up systemd (239-7ubuntu10) ...
Setting up udev (239-7ubuntu10) ...
update-initramfs: deferring update (trigger activated)
Setting up snapd (2.35.5+18.10) ...
snapd.failure.service is a disabled or a static unit, not starting it.
snapd.snap-repair.service is a disabled or a static unit, not starting it.
(Reading database ... 66334 files and directories currently installed.)
Preparing to unpack .../00-lxd_1%3a0.4_all.deb ...
Warning: Stopping lxd.service, but it can still be activated by:
  lxd.socket
=> Installing the LXD snap
==> Checking connectivity with the snap store
==> Installing the LXD snap from the latest track for ubuntu-18.10
error: cannot perform the following tasks:
- Setup snap "core" (5548) security profiles (cannot setup udev for snap "core": cannot reload udev rules: exit status 2
udev output:
)
- Setup snap "core" (5548) security profiles (cannot reload udev rules: exit status 2
udev output:
)
dpkg: error processing archive /tmp/apt-dpkg-install-R4N7rz/00-lxd_1%3a0.4_all.deb (--unpack):
 new lxd package pre-installation script subprocess returned error exit status 1
Preparing to unpack .../01-open-iscsi_2.0.874-5ubuntu9_amd64.deb ...
[...]


Interesting to me was that a subsequent
$ apt --fix-broken install
does fix it up.

Might there be an ordering issue in the snap/lxd updates that are not an issue for "real" Bionic->Cosmic upgraders?

(Reading database ... 66334 files and directories currently installed.)
Preparing to unpack .../archives/lxd_1%3a0.4_all.deb ...
Warning: Stopping lxd.service, but it can still be activated by:
  lxd.socket
=> Installing the LXD snap
==> Checking connectivity with the snap store
==> Installing the LXD snap from the latest track for ubuntu-18.10
2018-10-16T08:16:38Z INFO Waiting for restart...
lxd 3.6 from Canonical✓ installed
Channel stable/ubuntu-18.10 for lxd is closed; temporarily forwarding to stable.
==> Cleaning up leftovers
Synchronizing state of lxd.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install disable lxd
Removed /etc/systemd/system/multi-user.target.wants/lxd-containers.service.
Removed /etc/systemd/system/sockets.target.wants/lxd.socket.
=> Snap installation complete
Unpacking lxd (1:0.4) over (3.0.2-0ubuntu3) ...
Setting up lxd (1:0.4) ...
[...]