Installing LibreNMS: A Practical Setup Guide

LibreNMS is the device health layer of my observability stack. It polls switches and routers over SNMP, auto-discovers topology, and tracks performance history. Here is how to get it running.

Prerequisites

A dedicated LXC container or VM (Ubuntu 22.04/24.04 recommended)
2 vCPU, 2GB RAM minimum for small deployments (under 50 devices)
SNMP enabled on the devices you want to monitor

1. Install dependencies

sudo apt update && sudo apt upgrade -y
sudo apt install -y software-properties-common
sudo add-apt-repository universe
sudo apt install -y acl curl fping git graphviz imagemagick mariadb-client \
  mariadb-server mtr-tiny nginx-full nmap php php-cli php-curl php-fpm \
  php-gd php-gmp php-json php-mbstring php-mysql php-snmp php-xml php-zip \
  python3-pymysql python3-dotenv python3-redis python3-setuptools \
  python3-systemd rrdtool snmp snmpd unzip whois

2. Create the LibreNMS user and pull the code

sudo useradd librenms -d /opt/librenms -M -r -s "$(which bash)"
cd /opt
sudo git clone https://github.com/librenms/librenms.git
sudo chown -R librenms:librenms /opt/librenms
sudo chmod 771 /opt/librenms

3. Install PHP dependencies

sudo su - librenms
./scripts/composer_wrapper.php install --no-dev
exit

4. Configure MariaDB

sudo mysql -u root

CREATE DATABASE librenms CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
CREATE USER 'librenms'@'localhost' IDENTIFIED BY 'CHOOSE_A_STRONG_PASSWORD';
GRANT ALL PRIVILEGES ON librenms.* TO 'librenms'@'localhost';
FLUSH PRIVILEGES;
exit

5. Configure PHP timezone and web server

Set your timezone in /etc/php/*/fpm/php.ini and /etc/php/*/cli/php.ini:

date.timezone = "Your/Timezone"

Set up an Nginx site pointing to /opt/librenms/html with the PHP-FPM socket, then reload:

sudo systemctl restart nginx
sudo systemctl restart php*-fpm

6. Run the web installer

Visit http://your-server/install in a browser and complete the guided setup. It will validate PHP extensions, connect to the database, and create the admin account.

7. Enable SNMP polling and cron

sudo cp /opt/librenms/librenms.nonroot.cron /etc/cron.d/librenms

8. Add your first device

sudo su - librenms
./addhost.php <device-ip> <snmp-community> v2c
./discovery.php -h all
exit

Production notes from my own setup

I run LibreNMS inside an LXC container, isolated from config backup and alerting workloads, so a heavy SNMP polling cycle never starves other services
SNMPv2c is fine for internal segments; use SNMPv3 if any polling crosses an untrusted network
Autodiscovery via CDP/LLDP and BGP/OSPF peering saves significant manual device entry once your seed devices are added
Enable syslog-ng and snmptrapd integration early. Historical syslog data is far more useful once you actually need to look back at an incident

What I'd check before going to production

Confirm rrdtool and Redis are configured if you plan to scale past a handful of devices
Set up distributed poller mode if you have more than one site or a large device count
Back this box up like any other critical system. Your monitoring platform going down during an outage is the worst possible time to lose visibility