How can I extend unregistered docker images or dockerfiles? - docker

Question

Or maybe instead of using FROM there is a way to inject the contents of another dockerfile into the start of my own.

Answer 1

In any case you will need a base Operating System image to source from and then you can use the content of the "other" Dockerfile you want to use and append your own command and form a complete file.
For example the below line will just include the base OS layer:
FROM ubuntu
MAINTAINER Prasanjit Singh
And then add stuff from the borrowed docker file, say the below lines:
ENV USER root ENV PASS aiPeekai0AeZ2meephoolais7doo1thu
RUN \ apt-get update && \ apt-get -y install \
mysql-server-5.5 && \ rm -rf /var/lib/apt/lists/*
COPY my.cnf /etc/mysql/my.cnf COPY start.sh start.sh
VOLUME ["/var/lib/mysql"]
RUN rm /usr/sbin/policy-rc.d CMD ["/start.sh"]
EXPOSE 3306
And finally add your append your own(if any) and the file looks like this now:
FROM ubuntu
MAINTAINER Prasanjit Singh
ENV USER root
ENV PASS aiPeekai0AeZ2meephoolais7doo1thu
RUN \
apt-get update && \
apt-get -y install \
mysql-server-5.5 && \
rm -rf /var/lib/apt/lists/*
COPY my.cnf /etc/mysql/my.cnf
COPY start.sh start.sh
VOLUME ["/var/lib/mysql"]
RUN rm /usr/sbin/policy-rc.d
RUN rm /your/shell/script_or_command.sh # Add your stuff
CMD ["/start.sh"]
EXPOSE 3306
And you are done with the Dockerfile. Just build it and get your container launched. Let me know if it you need anything.