Recovery from Zigbee controller going OFFLINE

Openhabian openHAB 3.2.0.M4 on a Raspberry 4

Woke up this morning and all the Zigbee devices in the Openhab system were not working … after examining the log files I found that the USB Zigbee controller had gone offline:

Thing 'zigbee:coordinator_ember:ZigBee_Bridge' changed from ONLINE to OFFLINE (COMMUNICATION_ERROR)

After that, of course, no zigbee devices worked … I have no idea why this happened, recently I was out of the country for a month and the system ran flawlessly the entire time.

In the log just before the Zigbee controller went offline I saw hundreds (thousands?) of these:

[WARN ] [nding.zigbee.serial.ZigBeeSerialPort] - Processing DATA_AVAILABLE event: Serial buffer overrun

However, I get those periodically normally and it hasn’t resulted in the Zigbee controller going down, so not sure if it’s related…

Anyway, I am thinking to create a script that watches for the “ZigBee_Bridge” Thing going offline (with protecting during startup) and when that happens try a corrective action. So the question is, what is the best corrective action?

  1. Reboot the system - clearly will work
  2. Try to disable then re-enable the Zigbee controller - possibly will work.
  3. Something else?

Anyone else run into this and which is a better approach?