If you would like to use Docker as a non-root user, you should now consider adding your user to the “docker” group with something like:

sudo usermod -aG docker your-user

Remember that you will have to log out and back in for this to take effect!

• https://github.com/docker/distribution/blob/master/docs/deploying.md

docker image prune
docker volume prune

docker images
docker rmi -f $(docker images -q -a )

• https://docs.docker.com/engine/reference/builder/#healthcheck

FROM ...
HEALTHCHECK CMD curl --fail http://localhost || exit 1