[Mellanox] Fix issue: watchdogutil command does not work (#16091) - Why I did it watchdogutil uses platform API watchdog instance to control/query watchdog status. In Nvidia watchdog status, it caches "armed" status in a object member "WatchdogImplBase.armed". This is not working for CLI infrastructure because each CLI will create a new watchdog instance, the status cached in previous instance will totally lose. Consider following commands: admin@sonic:~$ sudo watchdogutil arm -s 100 =====> watchdog instance1, armed=True Watchdog armed for 100 seconds admin@sonic:~$ sudo watchdogutil status ======> watchdog instance2, armed=False Status: Unarmed admin@sonic:~$ sudo watchdogutil disarm =======> watchdog instance3, armed=False Failed to disarm Watchdog - How I did it Use sysfs to query watchdog status - How to verify it Manual test Unit test Conflicts: platform/mellanox/mlnx-platform-api/sonic_platform/watchdog.py platform/mellanox/mlnx-platform-api/tests/test_watchdog.py

[Mellanox] Fix issue: watchdogutil command does not work (#16091) - Why I did it watchdogutil uses platform API watchdog instance to control/query watchdog status. In Nvidia watchdog status, it caches "armed" status in a object member "WatchdogImplBase.armed". This is not working for CLI infrastructure because each CLI will create a new watchdog instance, the status cached in previous instance will totally lose. Consider following commands: admin@sonic:~$ sudo watchdogutil arm -s 100 =====> watchdog instance1, armed=True Watchdog armed for 100 seconds admin@sonic:~$ sudo watchdogutil status ======> watchdog instance2, armed=False Status: Unarmed admin@sonic:~$ sudo watchdogutil disarm =======> watchdog instance3, armed=False Failed to disarm Watchdog - How I did it Use sysfs to query watchdog status - How to verify it Manual test Unit test Conflicts: platform/mellanox/mlnx-platform-api/sonic_platform/watchdog.py platform/mellanox/mlnx-platform-api/tests/test_watchdog.py #6