Unable to upgrade ubuntu server from 14.04.4 to 16.04.1

I have been able to reproduce this issue several time by restoring a backup of this container and trying again.

~# apt-get install systemd-sysv
Reading package lists... Done
Building dependency tree
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 libc-dev-bin : Depends: libc6 (< 2.20) but 2.23-0ubuntu3 is to be installed
                Recommends: manpages-dev but it is not going to be installed
 libc6-dev : Depends: libc6 (= 2.19-0ubuntu6.9) but 2.23-0ubuntu3 is to be installed
 systemd-sysv : PreDepends: systemd
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

~# apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
  libapache-dbi-perl libtest-requires-perl libtime-modules-perl
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libc-dev-bin libc6-dev manpages
Suggested packages:
  glibc-doc man-browser
Recommended packages:
  manpages-dev
The following NEW packages will be installed:
  manpages
The following packages will be upgraded:
  libc-dev-bin libc6-dev
2 upgraded, 1 newly installed, 0 to remove and 369 not upgraded.
3 not fully installed or removed.
Need to get 0 B/3 240 kB of archives.
After this operation, 2 457 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
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Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/\${ <-- HERE ([^}]+)}/ at /usr/share/perl5/Debconf/Config.pm line 30.
Selecting previously unselected package manpages.
(Reading database ... 33169 files and directories currently installed.)
Preparing to unpack .../manpages_4.04-2_all.deb ...
Unpacking manpages (4.04-2) ...
Replacing files in old package libc-dev-bin (2.19-0ubuntu6.9) ...
Preparing to unpack .../libc6-dev_2.23-0ubuntu3_amd64.deb ...
Unpacking libc6-dev:amd64 (2.23-0ubuntu3) over (2.19-0ubuntu6.9) ...
Preparing to unpack .../libc-dev-bin_2.23-0ubuntu3_amd64.deb ...
Unpacking libc-dev-bin (2.23-0ubuntu3) over (2.19-0ubuntu6.9) ...
Setting up plymouth (0.9.2-3ubuntu13.1) ...
update-initramfs: deferring update (trigger activated)
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
insserv: Service udev has to be enabled to start service plymouth
insserv: exiting now!
update-rc.d: error: insserv rejected the script header
dpkg: error processing package plymouth (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of mountall:
 mountall depends on plymouth; however:
  Package plymouth is not configured yet.

dpkg: error processing package mountall (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of upstart:
 upstart depends on mountall; however:
  Package mountall is not configured yet.

dpkg: error proc...

As i had this issue again, i fixed it by removing postfix before doing the upgrade (apt-get remove postfix).

And another fix i found on 2 others containers was to remove an old init.d script from bind9, which only contained an exit 0 command (without the proper headers).

Status changed to 'Confirmed' because the bug affects multiple users.

I believe that I ran into the same issue while trying to run do-release-upgrade to upgrade my machine from 14.04.5 to 16.04.5.

It would seem that the problem is that the plymouth package does not properly depend on the udev package, so when both are being upgraded (as is done during do-release-upgrade), the postinst script for plymouth is run before the postinst script for udev. This causes the plymouth postinst to complain about the udev service not being enabled, which doesn't happen until after the udev postinst runs.

A log snippet from my do-release-upgrade run that shows udev postinst running after plymouth postinst:
```
Setting up plymouth (0.9.2-3ubuntu13.5) ...
update-initramfs: deferring update (trigger activated)
update-rc.d: warning: start and stop actions are no longer supported; falling back to defaults
insserv: Service udev has to be enabled to start service plymouth
insserv: exiting now!
update-rc.d: error: insserv rejected the script header
dpkg: error processing package plymouth (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up libpython-stdlib:amd64 (2.7.12-1~16.04) ...
Setting up gir1.2-glib-2.0:amd64 (1.46.0-3ubuntu1) ...
Setting up udev (229-4ubuntu21.15) ...
```

I can see from http://archive.ubuntu.com/ubuntu/pool/main/p/plymouth/plymouth_0.9.3-1ubuntu7.debian.tar.xz that the bionic version of plymouth does indeed have a dependency on udev. So perhaps this same dependency just needs to also be added to the xenial version?

Hello,

I've the same issue like Benjamin Curtiss..

As Ubuntu 14.04 will be soon EOL, it's complicated that we can't upgrade the OS from 14.04 to 16.04 right now..

I don't have postfix installed neither old init.d scripts on my server.