Well, it seems Octopress/Jekyll would like to have a locale set for UTF–8 support. I followed this (text in German) hint and now my Dockerfile looks like this:
# dockerfile for octopress FROM ubuntu:14.04 MAINTAINER krrrcks <firstname.lastname@example.org> ENV DEBIAN_FRONTEND noninteractive RUN apt-get update; \ apt-get -q -y upgrade RUN /usr/sbin/locale-gen en_US.UTF-8; \ update-locale LANG=en_US.UTF-8 RUN apt-get -q -y install git curl; \ apt-get clean RUN git clone git://github.com/imathis/octopress.git /opt/octopress RUN curl -L https://get.rvm.io | bash -s stable --ruby ENV HOME /root RUN echo "export LC_ALL=en_US.UTF-8" >> /root/.bashrc RUN echo "export LANG=en_US.UTF-8" >> /root/.bashrc RUN echo "source /usr/local/rvm/scripts/rvm" >> /root/.bashrc; RUN /bin/bash -l -c "source /usr/local/rvm/scripts/rvm; \ rvm install 1.9.3; \ rvm use 1.9.3; \ rvm rubygems latest; \ cd /opt/octopress; \ gem install bundler; \ bundle install; \ rake install" RUN echo "rvm use 1.9.3" >> /root/.bashrc WORKDIR /opt/octopress EXPOSE 4000 CMD ["/bin/bash"]
After playing around with Docker and Octopress I put the whole
/opt/octopress folder on my host machine and then restarted the image with the
-v flag. Therefore I can edit the files on my host machine with my favorite editor and use the container only for producing the HTML files, for preview and for publishing.
rake preview is a neat feature because the server always looks for changed files and produces the HTML files on the fly. That means I can edit the files in my editor and could see the resulting pages in a browser nearly the same time.