added installation instructions

README.md

@@ -1,4 +1,54 @@
-check_rasp_temp
-===============
+# check\_rasp\_temp
 
 Nagios-Plugin to check the CPU temperature of a Raspberry Pi
+
+
+## Installation
+This example uses a Raspberry Pi with Raspbian Wheezy and a Nagios server running Debian Wheezy.
+You might want to use other thresholds, e.g. the Raspberry in our server room is normally running at ~43°C so I have set the threshold to 45°C.
+
+#### Download Plugin
+```
+cd /usr/lib/nagios/plugins/ && \
+wget https://raw.githubusercontent.com/larsen0815/check_rasp_temp/master/check_rasp_temp && \
+chmod +x check_rasp_temp
+```
+
+#### Plugin needs to be run as root
+```
+cat <<EOF > /etc/sudoers.d/nagios_rasp_temp
+nagios ALL=(root) NOPASSWD: /usr/lib/nagios/plugins/check_rasp_temp
+EOF
+```
+
+#### Define NRPE command with thresholds
+```
+cat <<EOF > /etc/nagios/nrpe.d/rasp_temp.cfg
+command[check_rasp_temp]=sudo -u root /usr/lib/nagios/plugins/check_rasp_temp -w 60 -c 70
+EOF
+```
+
+#### Reload NRPE server
+```
+service nagios-nrpe-server reload
+```
+
+#### Define service on your Nagios host
+```
+define service{
+        use                     generic-service
+        hostgroup_name          raspberry-devices
+        service_description     Temperature
+        check_command           check_nrpe!check_rasp_temp
+}
+```
+
+#### Reload Nagios server
+```
+service nagios3 reload
+```
+
+#### Test your new check on your Nagios server
+```
+/usr/lib/nagios/plugins/check_nrpe -H #Raspberry_IP# -c check_rasp_temp
+```