On a QFX10008 the RE0 is exhibiting the alarm “CB 0 Ethernet Switch Failure” after a software upgrade. The other RE is in good shape.
Alarm seen:
Major CB 0 Ethernet Switch Failure
No traffic passing when RE0 is the Master. A RE switchover was done to bring the services back up via RE1.
1) Try soft restarting the CB with the following commands:
> request chassis cb slot 0 offline
> request chassis cb slot 0 online
2) If the problem persists, physically reseat it:
(Physically unplug it and connect it back)
** Some possible reasons for this behavior **
1. The firmware on the control board (CB) might not have been updated properly, causing compatibility issues between the new Junos version and the control board firmware.
2. Sometimes, residual processes or configurations from the previous version might interfere with the new software.
3. The initial boot-up after an upgrade involves running hardware diagnostics. If these diagnostics fail, it might incorrectly report hardware failures.
4. Occasionally, temporary glitches or state issues in the hardware may occur, especially if the upgrade process involved significant changes. Reseating the CB may clear these states and transient errors as it forces it to reinitialize and will run new hardware checks.
5. It's also possible the new Junos version introduced a bug that falsely reports hardware failures.