Munin plugin for USBTEMP.com temperature sensors

This is a Munin plugin for USBTEMP.com temperature sensors. These are DS18B20 1-wire sensors, basically attached to a Prolific USB serial. The munin plugin code for handling the USBTEMP sensor is based on the usbtemp-python3 module which was developed by Jaka. The original code has been used to derive a Munin plugin.

Running multiple sensors in parallel is supported. Each sensor has a ROM code ID to identify the sensor.

Install dependencies

This munin plugin requires python3-serial. Or should be available via the OS package management:

apt install python3-serial

Install plugin

To install the plugin, just put it into munin's plugin directory, usually under /etc/munin/plugins. Restart munin-node:

systemctl restart munin-node

Configuration

You may want to make customizations in /etc/munin/plugin-conf.d/munin-node configuration file, for example:

[usbtemp]
#user root
env.usbtemp_label_287902e50c0000e0 Rack temperature upper part
env.usbtemp_label_2833afe50c000085 Rack temperature bottom part
env.usbtemp_dev_pattern /dev/ttyUSB*

The hexdigit-part refers to a sensor's ROM code ID. You get the available sensor IDs by running:

# usbtemp_dev_pattern="/dev/ttyUSB*" /etc/munin/plugins/usbtemp
temperature_287902e50c0000e0.value 23.00
temperature_2833afe50c000085.value 23.81

Testing and debugging

1. Check if USB temperature sensors are attached using lsusb and ls -l /dev/ttyUSB*.

2. Run the /etc/munin/plugins/usbtemp directly with elevated privileges.

3. Connect to localhost:4949, enter list and check the output for usbtemp. Enter fetch usbtemp and check if it works.

4. Check munin-node's log files.