Looking around to get closer to the root cause
The problem seems to be the script running at shutdown.
I identified the corresponding file with:
find /etc/systemd -name *unattended*
which gaves me the related systemd script:
which then told me the script executed on shutdown:
Investigating deeper to find the root cause
within this script there is a section in line 120 related to the section in /etc/apt/apt.conf.d/50unattended-upgrades -> Unattended-Upgrade::InstallOnShutdown
Line 120 of /usr/share/unattended-upgrades/unattended-upgrade-shutdown:
if apt_pkg.config.find_b("Unattended-Upgrade::InstallOnShutdown", False):
The problem: it expects the keyword "False" while in the apt conf we should add "false" (exact string comparison)!
I was able to fix/workaround the stalling shutdown in 3 different ways:
- write "False" instead of "false" in /etc/apt/apt.conf.d/50unattended-upgrades
This setting is upgrade safe until a real fix is provided because the file we change here gets not overwritten by an update of unattended-upgrades.
Problem: When the root cause gets fixed this will result in a stalling shutdown again so I suggest to combine this with Workaround B.
OR: Workaround B
- decrease the wait time in /etc/systemd/system/shutdown.target.wants/unattended-upgrades.service from default to 15 seconds:
This setting is NOT upgrade safe because the file we change here may get overwritten by an update of unattended-upgrades. Besides this it is really far away from fixing something but it will ensure that your system will not wait several minutes when shutting down. Keep in mind that after an upgrade of unattended-upgrades you may have to set this again!
OR: Fix C (have to be reported upstream)
- fix /usr/share/unattended-upgrades/unattended-upgrades-shutdown to expect "false" instead of "False"
--- /tmp/unattended-upgrade-shutdown 2017-02-03 14:53:03.238103238 +0100
+++ /tmp/unattended-upgrade-shutdown_fix 2017-02-03 14:53:17.685589001 +0100
@@ -117,7 +117,7 @@
# run it
p = None
- if apt_pkg.config.find_b("Unattended-Upgrade::InstallOnShutdown", False):
+ if apt_pkg.config.find_b("Unattended-Upgrade::InstallOnShutdown", false):
env = copy.copy(os.environ)
env["UNATTENDED_UPGRADES_FORCE_INSTALL_ON_SHUTDOWN"] = "1"
logging.debug("starting unattended-upgrades in shutdown mode")
tbh only the last one is a real fix. the both other options are just workarounds until the real fix would be implemented.
This has to be done upstream and as this affects both Debian (tested on Debian Stretch) and Ubuntu (tested on Ubuntu 16.04.1) for both distributions.
I have opened a bug report here: https://bugs.launchpad.net/ubuntu/+source/unattended-upgrades/+bug/1661611