Recap part of April 2017
- We once again went over the CMD vs ENTRYPOINT since the concept was confusing.
ENV- Sets environment variables. Dockerfile can subsequently use set ENV vars (along with container).
WORKDIR- Sets the working directory to run commands from.
USER- Sets the working user for the container
- Otherwise it will run as ROOT
VOLUME- Attach a directory to the container
ADD- Copy content from a directory/zip to the container
COPY- Same as add except cannot do zip
LABEL- Adds a label to the image
STOPSIGNAL- System call to container when asked to stop. Values 1-9
ARG- Build arguments to pass to the container (like env variables except exposed during build so do not pass secrets)
SHELL- Sets the shell along with any default arguments for any subsequent RUN commands
HEALTHCHECK- FIle to use for checking on status of primary process. If check fails, container can automatically stop.
ONBUILD- Is a way to trigger generic docker images on a codebase. You can use this to create docker templates such as:
- Use an apache/php container that can make assumptions about the location of a codebase for serving the codebase to serve pages and expose the right ports
- Build a codebase using tools like
yarnand ```composer`` install`
- Is a way to trigger generic docker images on a codebase. You can use this to create docker templates such as:
We learnt to push images to dockerhub. Main command is docker push