Multi-Stage Dockerfile to prepopulated MySQL Image

Dockerfile

## See: https://serverfault.com/a/915845/17736
FROM percona/percona-server:5.7 as builder

USER root

RUN mkdir -p /initialized-db && chown -R mysql:mysql /initialized-db

# That file does the DB initialization but also runs mysql daemon, by removing the last line it will only init
RUN ["sed", "-i", "s/exec \"$@\"/echo \"not running $@\"/", "/docker-entrypoint.sh"]

# needed for intialization
ENV MYSQL_ROOT_PASSWORD=apidev

USER mysql

COPY *.sql /docker-entrypoint-initdb.d/

# Need to change the datadir to something else that /var/lib/mysql because the parent docker file defines it as a volume.
# https://docs.docker.com/engine/reference/builder/#volume :
#       Changing the volume from within the Dockerfile: If any build steps change the data within the volume after
#       it has been declared, those changes will be discarded.
RUN ["/docker-entrypoint.sh", "mysqld", "--datadir", "/initialized-db"]

FROM percona/percona-server:5.7

COPY --from=builder /initialized-db /initialized-db

USER root
RUN chown -R mysql:mysql /initialized-db

USER mysql
CMD ["--datadir", "/initialized-db"]

In Line 16 why are you putting the sql file into the /docker-entrypoint-initdb.d/ directory and not /initialized-db (which you later set as your data dir in stage #2)?

Disregard, Line 16 actually takes the .sql and places it in /docker-entrypoint-initdb.d/ which is actually used to initalize the DB when the /docker-entrypoint.sh script is executed.

Thanks for this example, it helped me in my implementation.