Tinkerforge Nagios Checks

Here you can find a collection of self written nagios checks for the tinkerforge system. As soon as i have the possibility to get a new brick or bricklet, i will update this repository with new checks. Feel free to send me some!

distance-ir-bricklet

The Nagios Tinkerforge Distance IR Bricklet check was built to get the distance the bricklet measures and compares that value against the minimum desired distance and the maximum desired distance given by a single desired distance and a threshold. Its provided as the check_tf_distance.sh script

The threshold can be calculated for each distance-ir-bricklet itself using the provided tf_distance_ir_bricklet_stddev_calc.sh script. It measures the distance once a second for a user-defined amount of total measurements and calculates the first standard deviation from it which will then provide the threshold for the nagios check.

For a good standard deviation, built up your bricklet with the desired distance it should measure later and run the script with some thousands of measurements (i recommend 7200 whereas the script will run about 2 hours in that case).

The nagios check itself then uses the standard deviation provided as the threshold to generate warnings if the measurement is larger than the first standard deviation and a critical if its more than the second standard deviation or twice the threshold.

How to get the standard deviation/check threshold?

1. Built up your test case with the desired distance you want to measure
2. Run the tf_distance_ir_bricklet_stddev_calc.sh script to get measurements and to calculate the standard deviation
   • bash tf_distance_ir_bricklet_stddev_calc.sh <distance_ir_bricklet_UID> <sample_points>
   • bash tf_distance_ir_bricklet_stddev_calc.sh hVu 7200
3. The script will output the standard deviation which is the threshold for the check itself
4. There is an example file (distance_ir_samples_20131106_232249.dat) with 30.000 sample points from a GP2Y0A02 sensor and a standard deviation of about 5

How to use the check?

1. Obviously you should know how to use nagios checks and this one works the same. Just an example.
   • check_tf_distance.sh <bricklet_uid> <desired_distance_in_mm> <measurement_threshold_in_mm>
   • in action: check_tf_distance.sh hVu 1000 12

How does a Nagios message look like?

Critical State

--SERVICE-ALERT-------------------
-
- Hostaddress: 10.0.0.1
- Hostname:    monitor.example.com
- Service:     Check Rack Door Distance: monitor.example.com
- - - - - - - - - - - - - - - - -
- State:       CRITICAL
- Date:        2013-11-06 18:30:14
- Output:      CRITICAL - Measured: 1438 mm, Expected: 1010 mm, Threshold: 5 mm
-
----------------------------------

Normal State

--SERVICE-ALERT-------------------
-
- Hostaddress: 10.0.0.1
- Hostname:    monitor.example.com
- Service:     Check Rack Door Distance: monitor.example.com
- - - - - - - - - - - - - - - - -
- State:       OK
- Date:        2013-11-06 18:34:50
- Output:      OK - Measured: 1010 mm, Expected: 1010 mm, Threshold: 5 mm
-
----------------------------------

Copyright and License

(c) 2013 Martin Seener

Released under the GNU GPLv2