Change of behavior: "dpkg-reconfigure -f noninteractive" unconditionally overwrites /etc/timezone now

[Hajo Möller]

In previous versions it was possible to set the system's timezone by editing /etc/timezone before running "dpkg-reconfigure -f noninteractive tzdata".

This behavior changed, /etc/timezone gets overwritten unconditionally during "dpkg-reconfigure -f noninteractive tzdata":
---
root@xenial:/# echo "Europe/Berlin" > /etc/timezone
root@xenial:/# cat /etc/timezone
Europe/Berlin
root@xenial:/# dpkg-reconfigure -f noninteractive tzdata

Current default time zone: 'Etc/UTC'
Local time is now: Tue Mar 8 23:09:39 UTC 2016.
Universal Time is now: Tue Mar 8 23:09:39 UTC 2016.

root@xenial:/# cat /etc/timezone
Etc/UTC
---

As a workaround to programmatically set the timezone one now needs to point "/etc/localtime" to the new timezone:
---
root@xenial:/# ln -fs /usr/share/zoneinfo/Europe/Berlin /etc/localtime
root@xenial:/# ll /etc/localtime
lrwxrwxrwx 1 root root 33 Mar 9 00:48 /etc/localtime -> /usr/share/zoneinfo/Europe/Berlin
root@xenial:/# cat /etc/timezone
Etc/UTC
root@xenial:/# dpkg-reconfigure -f noninteractive tzdata

Current default time zone: 'Europe/Berlin'
Local time is now: Wed Mar 9 00:49:05 CET 2016.
Universal Time is now: Tue Mar 8 23:49:05 UTC 2016.

root@xenial:/# cat /etc/timezone
Europe/Berlin
---

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[hackeron (hackeron)]

Any workaround for this? - How would one automate setting a timezone on 16.04?

[hackeron (hackeron)]

Ah, sorry, didn't read the report properly. Thank you for the workaround! -- Any workaround for echo "en_GB.UTF-8 UTF-8" > /var/lib/locales/supported.d/local?

[Michael Shadle (mshadle)]

Looks like for the time being this is the best:

# change this based on desired locale
ln -fs /usr/share/zoneinfo/US/Pacific-New /etc/localtime
dpkg-reconfigure -f noninteractive tzdata

ignore /etc/timezone, that seems to be properly reflected after the dpkg-reconfigure...

[DawnCold (loooseleaves)]

Michael's workaround works for me, but I'm waiting for fix release.

[Drors (drors)]

A simpler workaround that was OK for me:
rm /etc/localtime
dpkg-reconfigure -f noninteractive tzdata

After /etc/localtime is removed, it is regenerated properly.

[Mitar (mitar)]

A SO question has been asked about this: https://stackoverflow.com/questions/40234847/docker-timezone-in-ubuntu-16-04-image/43405380

[Ian Marsman (imarsman)]

FWIW, at least for a phusion Docker image which is based on Ubuntu 16.04, this workaround seems to work. As with most things in life related to computer administration there may be a wrinkle to this that I have not yet found.

ln -fs /usr/share/zoneinfo/America/Toronto /etc/localtime && printf 'America\nToronto\n' | dpkg-reconfigure tzdata

[Lars Kruse (devel-sumpfralle)]

According to the upstream package maintainer in Debian (Aurelien Jarno), /etc/localtime is the authoritive source of information, while /etc/timezone is just a Debian-specific artifact.

Thus the preferred approach for changing the timzone is indeed the change of the /etc/localtime symlink, followed by dpkg-reconfigure.

See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=813226#10 and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=848143#10.

[Dan Dascalescu (ddascalescu+launchpad)]

Please update https://help.ubuntu.com/community/UbuntuTime under "Using the Command Line (unattended)" with the new behavior.

[Benjamin Drung (bdrung)]

I documented how to change the time zone non-interactively in https://discourse.ubuntu.com/t/how-to-change-the-time-zone-in-ubuntu-using-the-command-line/35307 because the log-in to https://help.ubuntu.com/community/UbuntuTime timed out. As mentioned in the linked Debian bug reports and here, this change was intentional and /etc/timezone will go away soon. Therefore marking this bug as invalid.