First run of syncthing: re-use an old DeviceID

(5wl4omaa9k) #1

I use Syncthing on containers provided by a not-so-expensive GPU cloud hosting. The major drawback is that these containers have a short lifetime. So I frequently have to destroy a container and rebuild a new one. (Not possible to download it right now).

Problem: each time I rebuild a new container, I have a new ST DeviceID, so I have to redo the config on the container + redo the config on my local machine (add the new DeviceID to my local machine, re-share the folder to this new DeviceID), etc.

All would be simplified if on the first run of ./syncthing I could specify “Please reuse this existing DeviceID”:

./syncthing deviceid=ABCDEFG...XYZ

(there will never be a conflict between the 2 devices because when I do this on the new container, the old one is destroyed).

The gain would be that:

  • I wouldn’t have to add a new DevideID on my local computer’s ST
  • I woulnd’t have to re-share the local folder to a new device
  • If the new container has the same DeviceID, then he will automatically discover “DeviceHomeComputer wants to share this folder with you, do you accept?” and I would just have to press Yes.

How to do this?

(Jakob Borg) #2

Save the config.xml, cert.pem and key.pem files from the config directory. It’s not possible to “become” an existing device ID without those files - if it were, you could impersonate anyone.

(5wl4omaa9k) #3

Ok so just these 3 files and it will be ok?

Should I:

  1. Copy these 3 files in the config directory of the new container and then do the first launch of ./syncthing


  1. Do the first launch of ./syncthing, and then copy these 3 files in the config directory of the new container?

Thanks @calmh

(Jakob Borg) #4

Those files, yes. Before first launch. Or after, it doesn’t matter, but then you’ll overwrite the ones that have been created at first launch and have to restart Syncthing.