Unvolume in docker

Sometimes there is a need to use base image, but without any defined volumes. For example store some test data to database as image to easily revert it.
Currently and any time soon docker do not support removing volumes, ports and other image properties.
There is no UNVOLUME and UNEXPOSE and UNSETENV.
Several workarounds exists.



Edit image tar file

Just remove volumes from metadata.
There even tool for that
https://github.com/gdraheim/docker-copyedit

multistage build

Copy content of original image, without metadata
Use next dockerfile

# Dockerfile
FROM mysql as orig

FROM ubuntu:bionic as image
# care must be taken, this will not preserve fs ownership
COPY --from=orig / / # this will copy all files, without metadata.

ENV ... # include all commands that are not file related

ENTRYPOINT ["docker-entrypoint.sh"]

EXPOSE 3306
CMD ["mysqld"]