@louis-bouchard

"Started Unattended Upgrades Shutdown." means that the unit was started.
Since the patch assumes that we don't use "ExecStart" this means
nothing.

Upgrade procedure should be executed on "ExecStop". But it is not
happening. I tried to set debug info inside the "ExecStop" instead of
executing "unattended-upgrade-shutdown", but it doesn't work. I can
provide you with the detailed step-by-step instructions on how to 100%
reproduce the issue, but it will require KVM host, and running my
scripts which will deploy VM with LVM.

Basic steps:

* follow https://github.com/kayrus/deploy-vm docs
* git clone https://github.com/kayrus/deploy-vm
* cd deploy-vm
* ./deploy_vms_cluster.sh -o ubuntu -c xenial
* follow https://github.com/kayrus/rescue-initramfs docs
* and reinstall VM from initramfs using "deploy_os_lvm.sh" script

Then your Xenial VM will stuck at reboot

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to unattended-upgrades in
Ubuntu.
https://bugs.launchpad.net/bugs/1654600

Title:
  unattended-upgrade-shutdown hangs when /var is a separate filesystem

Status in unattended-upgrades package in Ubuntu:
  Fix Released
Status in unattended-upgrades source package in Xenial:
  Fix Committed
Status in unattended-upgrades source package in Yakkety:
  Fix Committed
Status in unattended-upgrades package in Debian:
  New

Bug description:
  [SRU justification]
  This fix is needed to make sure that the system does not hang on shutdown 
when /var is a speparate file system

  [Impact]
  System can hang up to 10 minutes if not fixed.

  [Fix]
  Change the systemd unit's ExecStart to an ExecStop so the unit is correctly 
sequenced.

  [Test Case]
  In a VM with /var separated from the / file system, shutdown the VM. It will 
hang for 10 minutes

  [Regression]
  None to be expected. A ExecStop unit will be sequenced before the Before= 
units which is earlier than previously.

  [Original description of the problem]
  The systemd unit file unattended-upgrades.service is used to stop a running 
unattended-upgrade
  process during shutdown. This unit file is running together with all 
filesystem
  unmount services.

  The unattended-upgrades service checks if the lockfile for unattended-upgrade
  (in /var/run) exists, and if it does, there is an unattended-upgrade in 
progress
  and the service will wait until it finishes (and therefore automatically wait 
at
  shutdown).

  However, if /var is a separate filesystem, it will get unmounted even though 
/var/run
  is a tmpfs that's still mounted on top of the /var/run directory in the /var 
filesystem.
  The unattended-upgrade script will fail to find lockfile, sleeps for 5 
seconds, and
  tries to check the lockfile again. After 10 minutes (the default timeout), it 
will finally
  exit and the system will continue shutdown.

  The problem is the error handling in 
/usr/share/unattended-upgrades/unattended-upgrade-shutdown
  where it tries to lock itself:

      while True:
          res = apt_pkg.get_lock(options.lock_file)
          logging.debug("get_lock returned %i" % res)
          # exit here if there is no lock
          if res > 0:
              logging.debug("lock not taken")
              break
          lock_was_taken = True

  The function apt_pkg.get_lock() either returns a file descriptor, or -1 on an 
error.
  File descriptors are just C file descriptors, so they are always positive 
integers.
  The code should check the result to be negative, not positive. I have 
attached a patch
  to reverse the logic.

  Additional information:

  1)
  Description:  Ubuntu 16.04.1 LTS
  Release:      16.04

  2)
  unattended-upgrades:
    Installed: 0.90ubuntu0.3
    Candidate: 0.90ubuntu0.3
    Version table:
   *** 0.90ubuntu0.3 500
          500 http://nl.archive.ubuntu.com/ubuntu xenial-updates/main amd64 
Packages
          500 http://nl.archive.ubuntu.com/ubuntu xenial-updates/main i386 
Packages
          100 /var/lib/dpkg/status
       0.90 500
          500 http://nl.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
          500 http://nl.archive.ubuntu.com/ubuntu xenial/main i386 Packages
  3)
  Fast reboot
  4)
  Very slow reboot (after a 10 minutes timeout)

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https://bugs.launchpad.net/ubuntu/+source/unattended-upgrades/+bug/1654600/+subscriptions

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