I spent two hours today trying to figure out why Nextcloud couldn’t read my data directory. Docker wasn’t mounting my data directory. Moved everything into my data directory. Docker couldn’t even see the configuration file.
Turns out the Docker Snap package only has access to files under the /home directory.
Moral of the story: never trust a Snap package.
It’s also offered as part of the installation process at least for Ubuntu server. If you don’t know better it bites you real quick.