This page introduces the external Watchdog. You will learn how to enable the watchdog and test it.

Watchdog is disabled by default, use the commands below to enable it.

khadas@Khadas:~$ sudo systemctl start external-watchdog.service

Check watchdog status:

khadas@Khadas:~$ systemctl status external-watchdog.service 
● external-watchdog.service - External Watchdog
     Loaded: loaded (/lib/systemd/system/external-watchdog.service; static)
     Active: active (running) since Mon 2022-08-22 11:19:31 CST; 1min 3s ago
   Main PID: 2766 (external-watchd)
      Tasks: 2 (limit: 1592)
     Memory: 1.5M
        CPU: 1.176s
     CGroup: /system.slice/external-watchdog.service
             ├─2766 /bin/bash /usr/local/bin/external-watchdog.sh start
             └─3157 sleep 0.5

You can also kill the watchdog daemon to prevent an automatic restart.

khadas@Khadas:~$ ps -axu | grep external-watchdog
root        2766  0.4  0.1   6876  3316 ?        Ss   11:19   0:01 /bin/bash /usr/local/bin/external-watchdog.sh start

Process ID with watchdog daemon is 2766.

khadas@Khadas:~$ sudo kill -9 2766

the system will automatically reboot.

khadas@Khadas:~$ sudo systemctl disable external-watchdog.service