In #10 the log shows that unattended-upgrades is asked to stop after 30 seconds and this is expected with the default configuration, when the configuration is changed only to enable InstallOnShutdown.
Please note that the behaviour of unattended-upgrades changed as described in the NEWS file. $ zless /usr/share/doc/unattended-upgrades/NEWS.Debian.gz unattended-upgrades (1.1ubuntu1.18.04.7~16.04.0) xenial; urgency=medium When InstallOnShutdown was configured unattended-upgrades in versions before 1.1ubuntu1.18.04.7~16.04.0 installed updates _after_ the shutdown transaction is started by systemd making maintainer scripts restarting services fail or wait in a deadlock until being killed by shutdown's timeout leaving a broken installation behind. Starting with version 1.1ubuntu1.18.04.7~16.04.0 configuring InstallOnShutdown makes unattended-upgrades start package installations _before_ the shutdown transaction is started, when PrepareForShutdown() signal is received via DBus. Unattended-upgrades 1.1ubuntu1.18.04.7~16.04.0 also increases logind's InhibitDelayMaxSec to 30 seconds. This allows more time for unattended-upgrades to shut down gracefully or even install a few packages in InstallOnShutdown mode, but is still a big step back from the 30 minutes allowed for InstallOnShutdown previously. Users enabling InstallOnShutdown mode are advised to increase InhibitDelayMaxSec even further, possibly to 30 minutes. In newer versions the configuration file also points this out, but the configuration file comment change was not SRU-d to avoid conflicts with locally changed configuration files: ... // Install all updates when the machine is shutting down // instead of doing it in the background while the machine is running. // This will (obviously) make shutdown slower. // Unattended-upgrades increases logind's InhibitDelayMaxSec to 30s. // This allows more time for unattended-upgrades to shut down gracefully // or even install a few packages in InstallOnShutdown mode, but is still a // big step back from the 30 minutes allowed for InstallOnShutdown previously. // Users enabling InstallOnShutdown mode are advised to increase // InhibitDelayMaxSec even further,q possibly to 30 minutes. //Unattended-Upgrade::InstallOnShutdown "false ... The problem on the system is that even preprocessing the available updates takes longer than 30 seconds, thus none of the updates can be applied. Speeding up the preprocessing part is ongoing, but it will still be recommended to bump logind's timeout. ** Changed in: unattended-upgrades (Ubuntu) Status: Confirmed => Invalid -- 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/1843099 Title: Unattended upgrades does not work on shutdown Status in unattended-upgrades package in Ubuntu: Invalid Bug description: 1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu * Ubuntu Xenial 16.04.6 LTS 2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center * 1.1ubuntu1.18.04.7~16.04.3 3) What you expected to happen * Packages to be upgraded on reboot / shutdown. 4) What happened instead * The host just rebooted. Didn't perform upgrades. No useful output either until I enabled debug logging in the systemd unit file. I'm reporting a new bug but this is very similar to #1806487 and I'm actually wondering if it resurfaced somehow. We're running Ubuntu Xenial 16.04.6 which has 1.1ubuntu1.18.04.7~16.04.3 installed. I see that #1806487 was resolved with 1.1ubuntu1.18.04.7~16.04.2. However I'm seeing similar behavior. So far I've modified systemd to see if anything stands out. I do have an strace and then just debug mode. Unless needed, simply put, this is what a reboot with debug logging looks like (i.e. unattended-upgrades-shutdown.log): 2019-09-06 09:20:04,871 DEBUG - Waiting for signal to start operation 2019-09-06 09:20:43,996 WARNING - SIGTERM or SIGHUP received, stopping unattended-upgradesonly if it is running 2019-09-06 09:20:43,996 DEBUG - Starting countdown of 25.0 minutes 2019-09-06 09:20:43,997 DEBUG - get_lock returned 7 2019-09-06 09:20:43,997 DEBUG - lock not taken I hope that helps, please let me know if you need anything else from me or if I can provide any more information. I've done this many times before, this is the first time it hasn't worked. When I patched around the end of May, all went well. My other variants worked, well mainly Trusty but that's EOL for public access. Bionic doesn't seem to have anything it needs to update. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unattended-upgrades/+bug/1843099/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp