Full SNMP Monitoring on Raspberry Pi 5 for LibreNMS (UCD-SNMP + Extend Workaround)

Date: May 14, 2025 Category: Monitoring / SNMP Backlink: LibreNMS Docker Deployment on Raspberry Pi 5 

 

 🧩 Overview 

 This update documents how I configured full-featured SNMP monitoring on a Raspberry Pi 5 running LibreNMS inside Docker. Since hrProcessorLoad and traditional Host Resources MIB features are often unavailable or broken on ARM-based systems, I used UCD-SNMP and NET-SNMP-EXTEND-MIB to monitor: 

 

 

 ✅ CPU usage 

 

 

 ✅ Memory usage (real, buffers, cache, swap) 

 

 

 ✅ Disk space 

 

 

 ✅ Temperature via custom script 

 

 

 ✅ Graphs and health sensors in LibreNMS dashboard 

 

 

 

 🔧 Step-by-Step Setup 

 1. Edit SNMP Configuration 

 Update /etc/snmp/snmpd.conf with: 

 rocommunity public

disk / 10000

view systemonly included .1.3.6.1.2.1.1

view systemonly included .1.3.6.1.2.1.25

view systemonly included .1.3.6.1.4.1.2021

view systemonly included .1.3.6.1.4.1.8072.1

extend temp /bin/bash /usr/local/bin/snmp-temperature.sh

 

 

 The disk line enables / monitoring. The extend line provides temperature monitoring. 

 

 

 2. Create Extend Script for CPU Temp 

 sudo nano /usr/local/bin/snmp-temperature.sh

 

 Paste: 

 #!/bin/bash

vcgencmd measure_temp | sed "s/temp=//;s/'C//"

 

 Make it executable: 

 sudo chmod +x /usr/local/bin/snmp-temperature.sh

 

 

 3. Give SNMP Access to Pi Temperature Sensor 

 sudo usermod -aG video Debian-snmp

sudo reboot

 

 

 4. Verify SNMP Outputs 

 snmpwalk -v2c -c public localhost .1.3.6.1.4.1.2021.4 # Memory

snmpwalk -v2c -c public localhost .1.3.6.1.4.1.2021.9 # Disk

snmpwalk -v2c -c public localhost hrProcessorLoad # CPU per core

snmpwalk -v2c -c public localhost .1.3.6.1.4.1.2021.10 # Load avg

snmpwalk -v2c -c public localhost NET-SNMP-EXTEND-MIB::nsExtendOutput1Line.\"temp\" # Temperature

 

 

 5. Ensure Pi is Added in LibreNMS 

 In the web UI: 

 

 

 Add device: 192.168.1.174 (not localhost ) 

 

 

 SNMP v2c, community public 

 

 

 Confirm SNMP test passes 

 

 

 

 📦 Inside the Docker Container 

 Enter container: 

 docker exec -it librenms bash

cd /opt/librenms

 

 Run poller and rediscovery: 

 php artisan config:clear

./lnms poller:discovery 1

./lnms device:poll 1

 

 

 📊 Final Results in LibreNMS 

 From the Pi's page: 

 

 

 Graphs → CPU, Memory, Storage, Temperature are all active 

 

 

 Health tab shows temperature sensor: temp1 

 

 

 Storage tab shows / and /boot/firmware 

 

 

 Dashboard Device Graphs widget now shows mini graphs for each metric 

 

 

 

 🩺 Troubleshooting Addendum 

 ❌ Memory Graphs Not Appearing? 

 Make sure: 

 

 

 SNMP returns .1.3.6.1.4.1.2021.4 correctly 

 

 

 ucd-mib , mempools , and storage modules are enabled in UI 

 

 

 You’ve updated the device hostname to use the Pi’s IP , not localhost 

 

 

 Use: 

 ./lnms poller:discovery 1

./lnms device:poll 1

 

 

 

 

 ✅ Wrap-Up 

 With this configuration, the Pi 5 running LibreNMS inside Docker is now monitoring itself via SNMP, including: 

 

 

 UCD-based metrics 

 

 

 Custom extend temperature sensor 

 

 

 Full graph integration 

 

 

 This setup is now replicable for other ARM-based Linux systems with similar SNMP limitations!