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Enable the Internal Watchdog Timer
The ComfilePi's SoC has an internal watchdog timer that can be used to automatically reboot the system should it ever become unresponsive.
First, verify that the /dev/watchdog device exists:
pi@raspberrypi:~ $ ls -al /dev/watchdog* crw------- 1 root root 10, 130 Feb 14 2019 /dev/watchdog crw------- 1 root root 251, 0 Feb 14 2019 /dev/watchdog0
Get more information about the watchdog configuration with `sudo wdctl`:
pi@raspberrypi:~ $ sudo wdctl Device: /dev/watchdog0 Identity: Broadcom BCM2835 Watchdog timer [version 0] Timeout: 15 seconds Pre-timeout: 0 seconds Timeleft: 14 seconds FLAG DESCRIPTION STATUS BOOT-STATUS KEEPALIVEPING Keep alive ping reply 1 0 MAGICCLOSE Supports magic close char 0 0 SETTIMEOUT Set timeout (in seconds) 0 0
Uncomment the following lines in the file /etc/systemd/system.conf:
RuntimeWatchdogSec=10 RebootWatchdogSec=10min
Install the watchdog service with the following commands:
sudo apt update sudo apt install watchdog
Check if the watchdog service is running with the following command:
pi@raspberrypi:~ $ systemctl | grep watchdog watchdog.service loaded active running watchdog daemon
If the watchdog.service is not running, start it with the following command:
sudo systemctl start watchdog.service
If you want the service to run automatically on each boot run the following command:
sudo systemctl enable watchdog.service
To test if the watchdog service is working, first, obtain root privileges and then initiate a forkbomb:
pi@raspberrypi:~ $ sudo su pi@raspberrypi:~ $ echo 1 > /proc/sys/kernel/sysrq pi@raspberrypi:~ $ echo "c" > /proc/sysrq-trigger
If the watchdog is working, then after about 10 to 20 seconds the ComfilePi should reboot.