Prometheus exporter for sensor data like temperature and fan speed.
lm-sensors (e.g. CPU/MB temp and CPU/Chassis fan speed) and hddtemp (HDD temperature from S.M.A.R.T. data) are included in the docker file.
See https://grafana.net/dashboards/237 for an example dashboard. This is probably way more than what you want, just mine the bits that are of interest and incorporate them into your general system health dashboard.
