I installed WebODM using the shell script to get it running in Docker. I could not get it to run from my ZFS raid (as a working directory) or to use an image or output location on that raid.
Turns out the issue is with the docker installation using snap. For some reason, docker within snap (as installed on ubuntu, but I don’t think that’s significant) won’t allow access to a ZFS dataset. That’s why I was seeing “file not found” for my .yml files that were very clearly present.
This isn’t a WebODM issue but I’m posting it for the benefit of anybody that comes after me. Ubuntu defaults to installing the docker snap when installing the headless ubuntu server edition, so I may not be the first person to get splinters in my forehead over this issue.