I was able to reproduce it in a freshly installed VM (VMware). ---------------------- root@ubuntu:~# egrep -v '(^\s*//.*$|^\s*$)' /etc/apt/apt.conf.d/50unattended-upgrades Unattended-Upgrade::Allowed-Origins { "${distro_id}:${distro_codename}"; "${distro_id}:${distro_codename}-security"; "${distro_id}ESM:${distro_codename}"; }; Unattended-Upgrade::Package-Blacklist { }; Unattended-Upgrade::Automatic-Reboot "true";
root@ubuntu:~# uname -a Linux ubuntu 4.4.0-104-generic #127-Ubuntu SMP Mon Dec 11 12:16:42 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux root@ubuntu:~# lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 16.04.3 LTS Release: 16.04 Codename: xenial root@ubuntu:~# apt-get update && apt-get dist-upgrade -y Get:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Hit:2 http://us.archive.ubuntu.com/ubuntu xenial InRelease Get:3 http://us.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB] Get:4 http://us.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB] Fetched 306 kB in 2s (146 kB/s) Reading package lists... Done Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. root@ubuntu:~# file /var/run/reboot-required /var/run/reboot-required: cannot open `/var/run/reboot-required' (No such file or directory) root@ubuntu:~# touch /var/run/reboot-required root@ubuntu:~# unattended-upgrades --dry-run (ssh disconnects, system reboots) root@ubuntu:~# cat /var/log/unattended-upgrades/unattended-upgrades.log 2017-12-16 09:59:17,772 INFO Initial blacklisted packages: 2017-12-16 09:59:17,773 INFO Initial whitelisted packages: 2017-12-16 09:59:17,773 INFO Starting unattended upgrades script 2017-12-16 09:59:17,773 INFO Allowed origins are: ['o=Ubuntu,a=xenial', 'o=Ubuntu,a=xenial-security', 'o=UbuntuESM,a=xenial'] 2017-12-16 09:59:21,610 INFO No packages found that can be upgraded unattended and no pending auto-removals 2017-12-16 09:59:21,611 WARNING Found /var/run/reboot-required, rebooting -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1269177 Title: Running 'unattended-upgrades --dry-run' reboots the machine To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unattended-upgrades/+bug/1269177/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs