Handle /etc/timezone on Debian systems about ansible-role-ntp

[geerlingguy]

Huh... TIL Debian works with timezones slightly different than RHEL (and, unless I'm missing something, different than pretty much all other distros?): https://wiki.debian.org/TimeZoneChanges

Debian wants the user to run dpkg-reconfigure tzdata to use a UI to select a TZ.

And it looks like it definitely has an effect on Java SDKs (http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-August/020229.html), and possibly cron (though I can't find definitive documentation for this). But most other things rely on /etc/localtime only...

I'm trying to figure out why Debian doesn't seem to follow the general standard here, and what the real difference between the two files is, before blindly just changing both files to the same value (in case there be dragons).

[geerlingguy]

Also from this answer, it looks like the best way to set this non-interactively is:

echo "Europe/Zurich" > /etc/timezone 
dpkg-reconfigure -f noninteractive tzdata

[gforcada]

I noticed that because jenkins (created with geerlingguy.jenkins of course, thanks a lot for all these awesome ansible roles btw!!) was showing a different timezone than expected.

So at least for java in general or jenkins in particular it has some effects.

[geerlingguy]

Yeah, it seems since Jenkins uses Java, it inherits the strange (to me) use of /etc/timezone instead of /etc/localtime for the default TZ data (from here):

1. If TZ environment variable is set, use that.
2. If /etc/timezone is readable, read the time zone from there.
3. If /etc/localtime is a symlink, resolve that, and use the name to guess the time zone.
4. Scan /usr/share/zoneinfo for a file whose contents match the contents of /etc/localtime.

[geerlingguy]

And it looks like on Debian systems, /etc/timezone is present, and as you mentioned, since it's not managed by this role, Java's not getting the configured timezone.

I'm testing a fix locally.

[geerlingguy]

I've pushed up a fix. If tests pass I'll tag a new release—it only makes this change/addition on Debian systems.

[gforcada]

Thanks!