Simplify configuration files tree

[federico-razzoli]

A manual inspection to look for an option takes an unreasonable amount of time.

[yosifkit]

Those are mostly inherited from the mysql packages for Debian; we only add docker.cnf:

mysql/5.7/Dockerfile

Lines 64 to 69 in 30bf2b7

	# comment out a few problematic configuration values
	&& find /etc/mysql/ -name '*.cnf' -print0 \
	| xargs -0 grep -lZE '^(bind-address|log)' \
	| xargs -rt -0 sed -Ei 's/^(bind-address|log)/#&/' \
	# don't reverse lookup hostnames, they are usually another container
	&& echo '[mysqld]\nskip-host-cache\nskip-name-resolve' > /etc/mysql/conf.d/docker.cnf

Most MySQL config can be specified later to override an earlier value:

$ docker run -d -e MYSQL_ROOT_PASSWORD=12345 mysql:5.7 --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci

[federico-razzoli]

This adds complexity, it's extremely error prone and it's hard to automate. It's better to reduce the number of files. But it would be nice if a simpler structure is provided by the image itself.

Ideally, from a user point of view, it would be even nicer to have the same structure in mysql image and mariadb image.

[ltangvald]

For the older versions, the structure was originally created in Debian because MariaDB also uses "mysql" file paths, so MySQL would have config in /etc/mysql/mysql.conf.d, MariaDB in /etc/mysql/mariadb.conf.d/, and shared options would be in /etc/mysql/conf.d/
So it's legacy of using the standard Debian packages, and I agree it's a bit much for the more self-contained Docker images.

However, the server itself only cares about /etc/mysql/my.cnf, so it's possible to change, and we did for 8.0.
The 8.0 images use the core packages that include no config, so we have a slightly simpler structure:
https://github.com/docker-library/mysql/tree/master/8.0/config

Does that look better to you?

[federico-razzoli]

Of course, this looks good. It's also very good that you reduced the number of settings in the files.

Any plans to port this to 5.7?