Docker and Server File locations?

So I know this is may be a noob question but working with some server testing I have run into a few problems. mainly file locations and specifically docker and rocketchat-server. I know snap spins up a separate “sandbox” instance (ex for docker /snap/docker) and all of the commands work but where are things like /var/lib/docker for image locations? How do I know where these things are? Is there some really good documentation that i’m missing? git seems silent and any snap tutorials are basically “this is how you run and stop isn’t this great!” When dealing with complex things like server instances that require a database, webserver and other directories how can I discover where all of these locations are?

This kind of all started because ubuntu 18.04 server installs the snap version of docker if you select that on initial install. It’s made my troubleshooting interesting. Any direction even if it’s “here’s the manual” would be appreciated.

Ok so I did find the docker section under /snap/docker/common/var-lib-docker. Still though, is this normal for all or would this specifically be how docker was setup?

Snaps with daemons in them will typically store their data in what’s called $SNAP_DATA which is /var/snap/SNAP_NAME/current.

You can find a listing of other environment variables/locations that snaps store their data here:

Thanks ijohnson. I will continue my adventure there