Posted on 31 August 2021
The Raspberry Pi has a hardware watchdog timer on its board that is able to restart the board. This is a super useful feature if you want your Pi to restart in the case of a system failure like a kernel panic or a process consuming all resources. This page explains how to set this up manually on a Pi.
Here’s the equivalent ansible playbook:
---
- hosts: all
become: yes
tasks:
- name: 'Enable watchdog in boot/config.txt'
import_role:
name: infothrill.rpi_boot_config
vars:
boot_config_lines:
- "dtparam=watchdog=on"
- name: 'Configure the watchdog'
import_role:
name: danmilon.watchdog
vars:
watchdog_device: /dev/watchdog
watchdog_timeout: 15
watchdog_realtime: yes
watchdog_priority: 1
watchdog_max_load_1: 24
To install dependancies:
ansible-galaxy install infothrill.rpi_boot_config
ansible-galaxy install danmilon.watchdog
The system should then restart automatically if you crash the system, e.g. by triggering a kernel panic:
# WARNING THIS WILL CRASH YOUR SYSTEM
echo c > /proc/sysrq-trigger
Some notes:
danmilon.watchdog which is not the usual watchdog role (that is whiskerlabs.watchdog). However, whiskerlabs don’t expose the watchdog-timeout setting that we must set on the Raspberry Pi.