docker image of moodle, is based in Alpine Linux and uses a php-fpm and nginx server.
It is base in the latest 3.3+ release for Moodle.
this image uses several environment variables:
The URL in wich this moodle will be installed.
Type of DataBase used for this image, the most common are mariadb and psql
IP address for the db connection
Name of the moodle database for create in the db
User of the database
Password for the database, is better use a file secret
File for db password for use in Docker secrets: the last line is the only valid one.