First of all, this bug report doesn't follow a template, in case you have one. I don't do templates. That's not me. I do free text.

I've been trying to setup wikimedia on docker, which is a little complicated to do because of the whole copying of LocalSettings.php shtick. You see, I want to make sure that my wiki works as intended for a long time which means I can not go around copying that file everytime I start up a new container. So I needed to find a solution where the LocalSettings.php file was read from a folder on my NAS which is tricky because of the whole mapping to a single file and not the folder stuff...

Anyway, that's not what this ticket is about. It's about the bad instructions.

"By default, this image does not include any volumes. The paths /var/www/html/images and /var/www/html/LocalSettings.php are things that generally ought to be volumes, but do not explicitly have a VOLUME declaration in this image because volumes cannot be removed."

That text makes no sense. Volumes can't be removed. Yes. That's a good thing. What, you want to remove them? I don't get what you're trying to say here, and it doesn't matter. You can just delete that and just write what mappings are needed.

So... I get from that that /var/www/html/images should be mapped to some host filesystem.
So I do that.

That's the extent of the instructions.

All fine and dandy, the wiki is running and I add a LOT of content. And hey ho, I get a skin or two, and some extensions, why not. And life is good. Right?

Wrong.

Because what happens when I need to drain that node on my swarm for a reboot, and the wiki gets started on another node?

Guess. Come on, guess.

Where are skins and extensions placed? UH OH! On the container that was just deleted, because you failed to document that those locations (and probably some other folders as well) need to be mapped to some filesystem as well for your application to function properly!