SNMP/Examples/Example 3:Extending SNMP

:SNMP can be extended by inserting the output of a command into the tree. This allows you to write scripts to fetch any information you like and monitor that data similar to interface statistics, RAM usage, and CPU load.
:This example feeds voltage, CPU fan speed, and CPU temperature information into the SNMP tree at OID .1.3.6.1.4.1.2021.54. First save the following to /root/bin/snmpsensors.

 #!/bin/bash
 Start sensors >/dev/null 2>&1
 sensors -c /usr/share/etc/sensors.conf >/dev/null 2>&1
 fields="$(sensors -c /usr/share/etc/sensors.conf|grep -vi isa |cut -f 2 -d : | awk '{print $1}')"
 for f in $fields ; do
   echo $f 1 '*' | dc
 done
 Stop sensors>/dev/null 2>&1

Then run chmod 755 /root/bin/snmpsensors
Last, add <code>exec .1.3.6.1.4.1.2021.54 sensors /root/bin/snmpsensors</code> to your SNMP configuration and restart SNMP.

The output of snmpwalk looks like this:

 rjune@rjune-desktop:~$ snmpwalk -v 2c -c public gw01 .1.3.6.1.4.1.2021.54
 UCD-SNMP-MIB::ucdavis.54.1.1 = INTEGER: 1
 UCD-SNMP-MIB::ucdavis.54.2.1 = STRING: "sensors"
 UCD-SNMP-MIB::ucdavis.54.3.1 = STRING: "/root/bin/snmpsensors"
 UCD-SNMP-MIB::ucdavis.54.100.1 = INTEGER: 0
 UCD-SNMP-MIB::ucdavis.54.101.1 = STRING: "1.76"
 UCD-SNMP-MIB::ucdavis.54.101.2 = STRING: "3.5"
 UCD-SNMP-MIB::ucdavis.54.101.3 = STRING: "4.8"
 UCD-SNMP-MIB::ucdavis.54.101.4 = STRING: "12.16"
 UCD-SNMP-MIB::ucdavis.54.101.5 = STRING: "5.26"
 UCD-SNMP-MIB::ucdavis.54.101.6 = STRING: "3.34"
 UCD-SNMP-MIB::ucdavis.54.101.7 = STRING: "8035"
 UCD-SNMP-MIB::ucdavis.54.101.8 = STRING: "35"
 UCD-SNMP-MIB::ucdavis.54.101.9 = STRING: "1.75"
 UCD-SNMP-MIB::ucdavis.54.102.1 = INTEGER: 0
 UCD-SNMP-MIB::ucdavis.54.103.1 = ""