18.04LTS here.

In my /etc/apt/apt.conf.d/50unattended-upgrades I have:

Unattended-Upgrade::Automatic-Reboot "true";

At the same time, /var/run/reboot-required exists.

When I exit the server and ssh in again, I can see * * * System restart required * * *.

So as far as I can see, the upgrading of packages using apt-get should now trigger an immediate restart if the restart is required, which I know it is (see above two reasons why I believe it is required).

However, I can't trigger the automatic reboot - I would expect it to be triggered by sudo apt-get upgrade but the command succeeds successfully and no restart happens.

What am I missing please?

Many thanks!

Contents of /etc/apt/apt.conf.d/20auto-upgrades :

APT::Periodic::Update-Package-Lists "1"; APT::Periodic::Unattended-Upgrade 1; APT::Periodic::Download-Upgradeable-Packages "0"; APT::Periodic::AutocleanInterval "7"; APT::Periodic::CleanInterval "7"; APT::Periodic::Verbose "0";

Contents of /etc/apt/apt.conf.d/50unattended-upgrades : Unattended-Upgrade::Automatic-Reboot "true"; Unattended-Upgrade::Automatic-Reboot-Time "+0";

1 Answer 1


You need to have update-notifier-common installed. This is not installed on minimal server installs by default

  • I do have it installed...
    – MartinH
    Dec 9, 2019 at 17:17
  • what is the conents of /etc/apt/apt.conf.d/20auto-upgrades
    – stratus
    Dec 9, 2019 at 17:46
  • have you tried setting Unattended-Upgrade::Automatic-Reboot-Time just to see whether it reboots?
    – stratus
    Dec 9, 2019 at 17:50
  • I've posted 20auto-upgrades file contents in the question. Also, trying Unattended-Upgrade::Automatic-Reboot-Time "+0"; or Unattended-Upgrade::Automatic-Reboot-Time "now"; doesn't make much difference. Running sudo apt-get upgrade doesn't lead to a restart when it should. Perhaps there is a service that needs to reload the contents of the two conf files?
    – MartinH
    Dec 11, 2019 at 13:35

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