I always run into issues installing Jellyfin on TrueNAS core. I fix them, and then I forget a few months later, so these are just my notes to myself of how to install Jellyfin on TrueNAS core.
Instructions
Install based on these instructions:
We need to follow the advanced instructions because TrueNAS plugins are deprecated.
Gotcha: Jellyfin server is not available
The first few loads after installing, an error will appear saying Jellyfin isn’t available. For some reason, waiting a few minutes fixed the issue and let me create a new account.
Mounting media
Go to Jails > Mount Points.
Mount the folder(s) of media to [pool root]/iocage/jails/jellyfin/root/media.
Mount as read-only.
Granting permissions
Open Jails > Jellyfin > Shell and type id jellyfin.
From the TrueNAS pool, add an ACL item for the uid of the Jellyfin user, specifying the jellyfin server’s uid instead of a username.
Adding libraries
The add library screen is strange and doesn’t give good feedback. Type /media and then hit the search button. If the permissions are set correctly, you should see subfolders of the mounted drive.