On behalf of Cypriot free software community (site In Greek https://ellak.org.cy ) I maintain and develop docker images for moodle. Recently I released varieties both for the lts and the latest version utilizing both apache and php-fpm, the latter one is relied upon alpine linux for minial image size.
The images are uplodaded into docker hub: https://hub.docker.com/r/ellakcy/moodle
Whilst the build script is located in github: https://github.com/ellakcy/docker-moodle
Do not hesitate to pull, remix or use it or even write an issue in github as well: https://github.com/ellakcy/docker-moodle/issues
Also we will be glad to merge your ideas into our code via a pull request (actually we are kinda in need for that).
With <3 the Cypriot Free Software Community.