Would it be acceptable to configure unattended-upgrades to automatically reboot the system when required? I already have it configured to check for and install all updates to Ubuntu and Tor once a day, but I still need to manually reboot to apply kernel upgrades.
I think
Unattended-Upgrade::Automatic-Reboot "true";
is a good practice for (lazy) tor servers operators to keep running patched kernels automatically, since automation usually reduces the time until the system is patched (and if necessary rebooted) - even if the operator does not follow security announce mailing lists.