Where do Docker containers get their time information? I’ve created some containers from the basic ubuntu:trusty image, and when I run it and request ‘date’, I get UTC time.
For awhile I got around this by doing the following in my Dockerfile:
RUN sudo echo "America/Los_Angeles" > /etc/timezone
However, for some reason that stopped working. Searching online I saw the below suggested:
docker run -v /etc/timezone:/etc/timezone [image-name]
Both these methods correctly set the timezone though!
$ cat /etc/timezone America/Los_Angeles $ date Tue Apr 14 23:46:51 UTC 2015
Anyone know what gives?
The secret here is that
dpkg-reconfigure tzdata simply creates
/etc/localtime as a copy, hardlink or symlink (a symlink is preferred) to a file in
/usr/share/zoneinfo. So it is possible to do this entirely from your Dockerfile. Consider:
ENV TZ=America/Los_Angeles RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
And as a bonus, TZ will be set correctly in the container as well.
This is also distribution-agnostic, so it works with pretty much anything Linux.
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