I ran into a problem that I will document here with the solution found. The problem and solution was a little surprise but educational. I hope that this description will help other users.
The test system is a new TrueNAS CORE host. Next an rsync push task is configured from a pool on a different TrueNAS Scale host (23.10.2) to the new TrueNAS CORE host (13.3-RELEASE).
I created an SSH keypair and SSH connection on the SCALE host for the new CORE host. Also, placed the public key from SCALE keypair to the root user on the CORE host.
This configuration is from TrueNAS Documentation.
As expected, the rsync push operation from SCALE to CORE succeeds.
Next, upgrade the TrueNAS CORE machine to TrueNAS SCALE (24.04.2). But this experiment is a clean install from the iso image and the configuration was manually recreated without bringing the configuration file from CORE. The additional step was to copy the public key to the root user of the new SCALE server.
I expected that the rsync tasks from the first SCALE server would run without change. But it failed with:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
remove with:
ssh-keygen -f "/tmp/tmpuyfndddb" -R "10.0.0.180"
Each time the rsync task runs a new tmp file is generated. TrueNAS middleware stores the host identification key internally. I pondered this for a while because my “normal” command line methods did not work in this case.
The solution is to reset the internal key value:
Credentials->Backup Credentials->SSH Connections->my_connection_to_remote
The selection “my_connection_to_remote” is the connection created for the TrueNAS CORE machine in the first step above.
The dialog box that opens includes the discovered remote key.
The solution is to press the “Discover Remote Host Key” button to replace the existing key with the new key.
After this step, the original rsync push task works as expected.