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[David Favor <david@xxxxxxxxxxxxxx>]

The systemd facility changes sysvinit behavior considerably, especially
sending no SIGKILL after SIGTERM.

Suggested solution, send SIGKILL after timeout, following SIGTERM.
________

Primary difference is systemd defers forever to underlying processes,
rather than shooting them in the head eventually.

This means processes which trap SIGTERM + never end, hang system
shutdown.

https://bugs.launchpad.net/ubuntu/+source/mysql-5.6/+bug/1468804
describes this problem with MySQL, not MariaDB, which does a very fast
shutdown.

Another culprit is fail2ban, which takes far to long to shutdown. I'll
push a shutdown fix for fail2ban shortly.

Worst offenders are /etc/rc.local processes, especially where a
supervisor program runs children + one or more children fail to die or
the supervisor restarts them when they die. Issuing - systemctl --no-
pager status rc.local.service - in a shell while issuing reboot in
another shell shows this problem.

The easiest way to debug a reboot hang is to run two shells + do reboot
in one.

Then a few seconds later issue - systemctl --no-pager status - in the
surviving shell. A quick scan of this output usually surfaces the
culprit.

Starting the attached script in /etc/rc.local as follows...

looper > /var/log/looper.log 2>&1

show systemd sends SIGTERM + never follows up with a SIGKILL, at least
within 5 minutes, which is when I killed the process myself to allow
reboot to finish shutdown + do restart.

net4-dev# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 15.10
Release:	15.10
Codename:	wily

net4-dev# uname -a
Linux net4.bizcooker.com 4.2.0-22-generic #27-Ubuntu SMP Thu Dec 17 22:57:08 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

** Attachment added: "looper"
   https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1528655/+attachment/4539392/+files/looper

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https://bugs.launchpad.net/bugs/1528655

Title:
  Wily/15.10 - systemd hangs reboot + shutdown for long periods of time

Status in systemd package in Ubuntu:
  New

Bug description:
  Yet another horrible bug related to systemd which delays shutdowns by
  minutes.

  https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/1374759
  surfaces this problem + the bug I'm reporting here is a separate
  issue.

  Neither reboot or shutdown -r now work sensibly any more. Both rely on
  systemd, which appears to be the root of most Ubuntu instabilities
  now, reading the many reported systemd bugs.

  Both the reboot + shutdown -r now commands should do what the mean.
  Shutdown + Reboot now...

  Not 150-250 seconds after requested, which appears to be some
  arbitrary systemd timeout.

  Please fix this problem + update this ticket with some workaround to
  get an instant reboot, till fix is available.

  Thanks.

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