224

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?

3
  • 4
    If you use Alpine, you need to install tzdata first, see here github.com/gliderlabs/docker-alpine/issues/136
    – Belter
    Dec 27 '17 at 14:56
  • 2
    FYI . . . I wish to set the timezone of container at docker run time not at docker build/dockerfile time. Using -v /etc/localtime:/etc/localtime:ro (CentOS) sort of works. Inside container command-line date returns date in the expected timezone format. BUT jenkins running in container thinks timezone is UTC. Why? /etc/localtime is a symlink to ../usr/share/zoneinfo/UTC in built container. The content of the UTC file in container is now the new timezone. But jenkins (and perhaps other java based software) use the name of the symlink which is still "UTC". Searching for solution . . .
    – gaoithe
    Jan 21 '19 at 17:29
  • 1
    Need 2 things, 1. when container is created use an init script to set /etc/localtime symlink and /etc/timezone and 2. for jenkins timezone is taken from two java options, these options need to be passed to the init script which starts the jenkins process. e.g. " -Dorg.apache.commons.jelly.tags.fmt.timeZone=America/New_York -Duser.timezone=America/New_York ". Apologies, this is jenkins specific but hopefully useful for some other jenkins users.
    – gaoithe
    Jan 22 '19 at 16:59

11 Answers 11

336

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 any Linux.

Note: if you are using an alpine based image you have to install the tzdata first. (see this issue here)

Looks like this:

RUN apk add --no-cache tzdata
ENV TZ America/Los_Angeles
14
  • 36
    List of TZ names: en.wikipedia.org/wiki/List_of_tz_database_time_zones
    – BillyTom
    Aug 14 '17 at 9:19
  • 10
    With Ubuntu:16.04 (and maybe others version) you need to have tzdata package installed for make this work.
    – Opsse
    Oct 23 '17 at 1:29
  • 12
    Am I the only one who thinks it is not very smart to hardcode a timezone in the Dockerfile?
    – Wolfgang
    Nov 2 '18 at 15:39
  • 2
    @Wolfgang This is an example. You can provide it in any other way you would ordinarily provide environment variables, such as the command line, docker-compose.yml, etc. Nov 2 '18 at 15:42
  • 4
    I noticed that, at least for Alpine-based images, just setting the TZ variable was enough. I didn't have to setup the symlinks or anything else.
    – code_dredd
    Jun 21 '19 at 21:54
103

Usually it is sufficient to set an environment variable in the docker container, like so:

docker run -e TZ=Europe/Amsterdam debian:jessie date

Of course this would work also with docker-compose.

3
  • 7
    This seems to be the most elegant way. Take care that some base image, like ubuntu:16.04, does not have the tzdata package which should be added in Dockerfile. May 19 '17 at 10:25
  • 2
    +1 -- I agree with Julien; this appears to be the most elegant approach for setting time zones at runtime. This works well with CentOS. Alpine image does require installation of 'tzdata' package, which is preferred over harcoding configurations at build time unless the extra 3MB image payload cannot be tolerated :)
    – Frelling
    Dec 27 '17 at 16:09
  • This seems good but seems to not work for me (with CentOS 7.5.1804 and tzdata-2018e-3.el7.noarch) ? sad face
    – gaoithe
    Jan 21 '19 at 17:19
34

You can add your local files (/etc/timezone and /etc/localtime) as volume in your docker-container.

Update your docker-compose.yml with the following lines.

volumes:
    - "/etc/timezone:/etc/timezone:ro"
    - "/etc/localtime:/etc/localtime:ro"

Now the container time is the same as on your host

8
  • 1
    If your on CentOS distrib host enter the command echo "Europe/Paris" > /etc/timezone before restarting the container.
    – CrazyMax
    Sep 18 '17 at 13:21
  • Does this work on MacOS host?
    – Redsandro
    Oct 26 '17 at 23:24
  • 2
    Does not WORK in MAC Jan 19 '18 at 3:08
  • 4
    This will corrupt your zoneinfo db as /etc/localtime is a symlink (thus /usr/share/zoneinfo/Some/Thing is likely to get mounted as /usr/share/zoneinfo/UTC inside the container). Not to mention that you'd mix the db file from the host with the one in the container.
    – ionelmc
    May 10 '18 at 15:03
  • 2
    WARNING: This can cause strange bugs! See github.com/nodejs/node/issues/28743. At the very least you should mount /usr/share/zoneinfo as well. Jul 8 '20 at 10:24
22

Mounting /etc/localtime in the image, so it is in sync with host -v is the most popular one.

But see issue 12084:

it is not correct because it does not work when the software requires instead the file /etc/timezone to be set.
That way you are using leaves it as the default value etc/UTC.

I have determined that actually there is no foolproof elegant way to set the time zone inside of a docker container.
So have finally settled on this solution:

App dockerfile:

# Relocate the timezone file
RUN mkdir -p /config/etc && mv /etc/timezone /config/etc/ && ln -s /config/etc/timezone /etc/

App entrypoint script:

# Set timezone as specified in /config/etc/timezone
dpkg-reconfigure -f noninteractive tzdata

Data volume /config dockerfile, localized to a specific country or region:

# Set the time zone
RUN echo "Europe/London" > /config/etc/timezone

... it is not elegant because involving 3 separate files, and re-creating /etc/localtime on every runtime container start. Which is rather wasteful.

However it does work properly, and successfully achieve separation between the base app image, and each per-country localized configuration.
In 3 lines of code.

2
17

In ubuntu 16.04 image there is bug. Solution was

    ENV TZ 'Europe/Tallinn'
    RUN echo $TZ > /etc/timezone && \
    apt-get update && apt-get install -y tzdata && \
    rm /etc/localtime && \
    ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && \
    dpkg-reconfigure -f noninteractive tzdata && \
    apt-get clean
2
  • 2
    Seriously...this is the only solution that worked!
    – Gerrat
    Jun 30 '17 at 22:13
  • 1
    Also had to do this - seems tzdata is no longer in some distros by default.
    – Peter
    Jan 24 '18 at 7:06
4

if you are using docker image based on ubuntu :

# Change the docker default timezone from UTC to SGT
echo "Asia/Singapore" > /etc/timezone
dpkg-reconfigure tzdata
date
4

Adding my two cents here, because I've tried several of these but none worked on alpine-based images.

However, this did the trick:

ENV TZ=America/Toronto
RUN apk update
RUN apk upgrade
RUN apk add ca-certificates && update-ca-certificates
RUN apk add --update tzdata
RUN rm -rf /var/cache/apk/*

[Source]

4

In alpine basic Image (example use node:10.16.0-alpine):

Dockerfile

FROM node:10.16.0-alpine

ENV TZ=America/Los_Angeles

RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

WORKDIR /app

COPY package.json package-lock.json ./

RUN npm i --production

COPY . .

CMD node index.js

3

Thanks to VonC for the information and link to the issue. This seems like such a convoluted mess, so I did some testing on my own idea of how to solve this and it seems to work great.

>docker run -it ubuntu:trusty /bin/bash
#dpkg-reconfigure tzdata

(follow prompts to select my timezone)

>docker commit [container-id] chocko/ubuntu:local

Then I updated my Dockerfiles to reflect this:

FROM chocko/ubuntu:local

There must be something wrong with this because it seems too easy to be overlooked... Or is this acceptable?

2
  • This is also what I tried, but the timezone still resets itself after I exit the container. This is on Debian. Jun 9 '17 at 4:57
  • @MikeChamberlain did you happen to try the accepted answer by Michael Hampton above? I haven't implemented it myself, but I reckon it's the way to go considering the upvotes that it has received. Jun 9 '17 at 17:00
3

Using a Fedora container (likely to work with ubuntu also):

The simplest solution I found was to use the following in docker-compose.yml

environment: 
  TZ: "${TZ:-America/Los_Angeles}"

Then in your .env file (which docker-compose automatically reads)

TZ=America/Los_Angeles

This allows you to put docker-compose.yml under version control and use a customized .env file which can be ignored by git.

You get a default value for the container and you get customization, best of both worlds.

For Fedora no other changes were necessary, it just works!

2

A more generic way to set the timezone in docker run arguments:

-e TZ=`ls -la /etc/localtime | cut -d/ -f8-9`

Or for reuse:

function GET_TZ () {
    ls -la /etc/localtime | cut -d/ -f8-9
}

...
-e TZ=`GET_TZ`
1
  • 1
    doesn't help if your base image is alpine(5MB) which doesn't has the "tzdata" installed
    – max4ever
    Jun 21 '19 at 14:05

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