[Preview][Testing] Media server migration

[0xSysR3ll]

This is a proper discussion for users who want to test the Media Server Migration preview image.

Please, carefully read the instructions below before testing anything. I (as the author of the PR) won't be responsible if you break your production instance.

Caution

Work in progress

This feature is still experimental. Do not use it on a production instance unless you have a verified backup and a tested rollback plan.
See Backups.

Also, don't use this image if you did not migrate to at least Seerr v3.1.0

This PR adds an in‑app way to switch a single Seerr instance between media servers (Plex <=> Jellyfin/Emby) without losing users, permissions, requests, or general settings.
The same database and application instance are reused; only the active media server and authentication method change.

The goal is to make media‑server migrations practical without needing a second Seerr instance or manual database edits. You (the owner) configure the new server, users link their new accounts, and then the instance is switched in place.

Note

This will initially ship as a preview so the flow can be tested and refined properly.

Migration flow (preview)

1. Back up first

   • Follow the official guide: Backups.

2. Switch to the preview image

   • Stop seerr.
   • Change the image tag to preview-media-server-migration
   • Start Seerr

3. Configure your target media server

   • Plex => Jellyfin/Emby: configure Jellyfin/Emby in the Jellyfin settings tab.
     API key will be needed.
   • Jellyfin/Emby => Plex: configure Plex in the Plex settings tab.

Warning

Jellyfin <=> Emby is not a supported migration path, at least not properly tested yet.

5. Have users link their accounts

   • Users go to Profile => Linked accounts and link their account on the target media server.
   • (Optional) In Settings => Users, verify who has "Plex linked" or "Jellyfin/Emby linked".

6. Switch media server in settings

   • As an admin, open Settings => General.
   • Use the "Switch media server" section to choose the target server and confirm.

7. Restart and sign in again

   • After a successful switch, all users are logged out.
   • Restart Seerr, then have users sign in with the new account they linked.

8. Verify your data

   • Confirm users, permissions, requests, and general settings look correct.
   • If anything went wrong, restore from your backup and report the issue.

9. Go back to production image

   • Stop Seerr
   • Change the image tag back to latest or v3.1.0
   • Start Seerr