Getting apps to work in cutting edge Ubuntu Docker containers when they grizzle about locales.

Whilst running up an Artful Aardvark Ubuntu docker container on a Zesty Ubuntu host server, I received a message that it couldn't load certain apps due to the locales for UTF-8 were not configured.

This was annoying, but I initially worked around it , by installing the locales-all package into the container - it worked - but it bloated the container considerable.

There is a better and simpler way, which I found after a lot of digging around in the Docker documentation, as others must have hit this issue before.

What you need to do is set the following env variable in your Dockerfile when you build your container, and the problem does get solved for most apps, like tmux and screen within the container.

ENV LANG C.UTF-8

If you find that this doesn't cure it for your application , you may need to move to the next step and include the following in your Dockerfile.

       
RUN apt-get update && apt-get install -y locales \
&& rm -rf /var/lib/apt/lists/* \
&& localedef -i en_US -c -f UTF-8 -A \
/usr/share/locale/locale.alias en_US.UTF-8
ENV LANG en_US.utf8