removed robots do not come back after hub restart

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

One or more robots has been removed from the hub, usually with one of the following methods:

• removerobot callback
• removeallrobots callback
• robot.sds was deleted

After restarting the hub, the active robots do not come back.

A message similar to the following is seen in the controller.log on all impacted robots:

 Controller: failed to send alive to hub (hubname) (IP address) - not found
 Controller: failed to send alive (async) to hub (hubname) (IP address) - not found

 

A message similar to the following is seen in the hub.log of the corresponding hub at the same time:

 hub: alive - (robot name) (IP address) is a valid controller
 hub: SREPLY: status = 4(not found) ->(IP Address/port)

 

Environment

DX UIM 23.4.7 or prior
controller/robot_update 23.4.7 or prior
hub - any version

Cause

robot fails to re-register successfully with the hub

Resolution

Starting in robot_update/controller version 23.4.8 a new retry behavior will be introduced that forces the robots to more reliably re-register with the hub when this occurs.

This will be released with DX UIM 23.4.8 (DX UIM 23.4 CU8) approximately July 2026.

Meanwhile, as a workaround, try the following:

• stop the hub entirely and wait a full 5 minutes to force the robots into a more aggressive re-registration mode, then start the hub.  Robots should re-register within a few minutes.
• If any robot does not re-register, it must be manually restarted