Comment 3 for bug 1615482

Separating out u-u from the rest of the apt maintenance script could be useful, but I prefer running the update, package fetch, upgrade then cache clean up all in one hit. You *can* delay your reboot time, but the shutdown command, at least pre-systemd would run until the shutdown happens, periodically issuing a message to all terminal users before stopping further logins and finally changing the runlevel to reboot the machine. Less than ideal in the old cron.daily days, as those jobs run sequentially and in lexical order. And a is for apt.

In the mixed jessie, trusty, xenial environment we run, we've moved to taking the apt job out of cron.daily entirely, running the reboot 'now', and using the cron/timer start time to effectively schedule the reboot.

My grievance is mainly that in making the transition to systemd the upstream developers chose to:

1) Significantly change the job start time behaviour
2) Not bother to mention this behaviour change in the the changelog

It would be good to see Ubuntu at least set the timer defaults in such a way that enabling unattended upgrades doesn't result in nasty reboot during the day default behaviour. Which, given the half hour random start time default, should be achievable without putting undue load on the servers.