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Monitoring Instances with LibreNMS on Ubuntu Noble Numbat (24.04)

Reviewed on 02 January 2025 • Published on 04 July 2019

LibreNMS
Ubuntu
Focal-Fossa

Learn how to use LibreNMS to monitor Instances on Ubuntu 24.04 (Noble Numbat). LibreNMS is an open-source network monitoring system supporting a wide range of network hardware and operating systems, including Linux and Windows.

The software is based on PHP and MySQL (MariaDB) and is a community-based fork of the last GPL-licensed version of Observium.

Before you startLink to this anchor

To complete the actions presented below, you must have:

A Scaleway account logged into the console
Owner status or IAM permissions allowing you to perform actions in the intended Organization
An SSH key
An Instance running on Ubuntu Noble Numbat (24.04)
A domain or subdomain pointed to your Instance

Installing LibreNMSLink to this anchor

Update the apt package cache and upgrate the already installed system packages:

apt update && apt upgrade -y

Install the required packages.

apt install -y acl curl composer fping git graphviz imagemagick mariadb-client mariadb-server mtr-tiny nginx-full nmap php-cli php-curl php-fpm php-gd php-json php-mbstring php-mysql php-snmp php-xml php-zip python3-memcache python3-mysqldb python3-pip rrdtool snmp snmpd whois

Create a user for LibreNMS:

useradd -r -M -d /opt/librenms librenms
usermod -aG librenms www-data

Download and configure LibreNMS:

git clone https://github.com/librenms/librenms.git /opt/librenms
chown -R librenms:librenms /opt/librenms
chmod 770 /opt/librenms
setfacl -d -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/
setfacl -R -m g::rwx /opt/librenms/rrd /opt/librenms/logs /opt/librenms/bootstrap/cache/ /opt/librenms/storage/

Install PHP dependencies:

sudo -u librenms bash
cd /opt/librenms
./scripts/composer_wrapper.php install --no-dev
exit

Setting up the databaseLink to this anchor

LibreNMS stores the data collected from the monitored systems in a MySQL database. The open-source fork MariaDB is used in the setup, providing the same features as MySQL.

Run the MariaDB setup assistant to configure a secure root password for the database server:
```
mysql_secure_installation
```

Connect to the MariaDB shell with the user root and the password configured in the previous step:

mysql -uroot -p

Create a database and user for LibreNMS and grant permissions to the database:

CREATE DATABASE librenms CHARACTER SET utf8 COLLATE utf8_unicode_ci;
CREATE USER 'librenms'@'localhost' IDENTIFIED BY '<a_secure_password>';
GRANT ALL PRIVILEGES ON librenms.* TO 'librenms'@'localhost';
FLUSH PRIVILEGES;
exit

Replace <a_secure_password> with a secure password of your choice.

Open the file /etc/mysql/mariadb.conf.d/50-server.cnf in a text editor, for example nano:

nano /etc/mysql/mariadb.conf.d/50-server.cnf

Add the following Lines within the [mysqld] section:

innodb_file_per_table=1
lower_case_table_names=0

Save the file by pressing CTRL+O and exit nano by pressing CTRL+X.

Restart the MariaDB server:

systemctl restart mysql.service

Setting up NginxLink to this anchor

Nginx is an open-source web server and is being used to serve the web frontend of LibreNMS.

Create the file /etc/nginx/sites-available/librenms.example.com by opening it in a text editor:

nano /etc/nginx/sites-available/librenms.example.com

Add the Nginx configuration to the file, save it, and exit nano:

server {
listen      80;
server_name <librenms.example.com>;
root        /opt/librenms/html;
index       index.php;
charset utf-8;
gzip on;
gzip_types text/css application/javascript text/javascript application/x-javascript image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon;
location / {
  try_files $uri $uri/ /index.php?$query_string;
}
location /api/v0 {
  try_files $uri $uri/ /api_v0.php?$query_string;
}
location ~ \.php {
  include fastcgi.conf;
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
}
location ~ /\.ht {
  deny all;
}
}

Important

Replace <librenms.example.com> with the FQDN of your Instance.

Enable the server block by linking it to the sites-enabled directory:

ln -s /etc/nginx/sites-available/librenms.example.com /etc/nginx/sites-enabled/

Restart the Nginx web server:

service nginx restart

For security reasons, it is recommended to configure HTTPS by following this tutorial.

Setting up SNMPLink to this anchor

Simple Network Management Protocol (SNMP) is a protocol for collecting and organizing information about managed devices on IP networks. Data of SNMP is transported using User Datagram Protocol (UDP). Requests are sent to the agent listening on UDP port 161.

Copy the SNMP configuration file in the directory /etc/snmp:

cp /opt/librenms/snmpd.conf.example /etc/snmp/snmpd.conf

Open the configuration file in a text editor:

nano /etc/snmp/snmpd.conf

Edit the string RANDOMSTRINGGOESHERE to an SNMP group name of your choice.

Save the file and exit nano.

To display distribution information, download the distro script and make it executable:

curl -o /usr/bin/distro https://raw.githubusercontent.com/librenms/librenms-agent/master/snmp/distro
chmod +x /usr/bin/distro

Restart the SNMP service:

systemctl restart snmpd.service

Setting up the cronjob and logrotateLink to this anchor

Cron is a job scheduler available on Linux systems. It can be used to run jobs (i.e. shell scripts) automatically at given points in time to automatize system maintenance. Logrotate is a tool to rotate log files automatically. This means cleaning up log files periodically by removing old contents to ensure the disk space they occupy does not exceed a configured maximum value.

Copy the cron configuration file into the directory /etc/cron.d/ to execute actions automatically:

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

The file contains the basic cronjobs required by LibreNMS.

To prevent the log files of LibreNMS from becoming too large, logrotate can rotate them out from time to time to save space. Enable it by copying the provided configuration file into /etc/logrotate.d:

cp /opt/librenms/misc/librenms.logrotate /etc/logrotate.d/librenms

Running the web installerLink to this anchor

Open a web browser and go to your LibreNMS Instance:

https://librenms.example.com/install.php

Fill in the database connection parameters and the password set during database creation:
Configure a user and password for LibreNMS and complete the setup.2. Fill in the database connection parameters and the password set during database creation:
Configure a user and password for LibreNMS and complete the setup.

Adding localhost to LibreNMSLink to this anchor

Start by adding the local host as the first device to monitor:

Once logged in, click Devices, then Add Device in the pop-up menu:
Enter the hostname localhost, keep SNMP on, leave the values for SNMP version and Port Association Mode as preset. Enter the configured community name in the file /etc/snmp/snmpd.conf as the value for Community. Once all values are set, click Add Device to add the device:
LibreNMS starts polling the device and different graphs are created, showing the status of the device.

Adding a remote device to LibreNMSLink to this anchor

LibreNMS is capable of monitoring many network devices. To monitor a remote cloud Instance or Elastic Metal server, the use of SNMP is widespread. SNMP stands for Simple Network Management Protocol. It is a protocol that was designed for monitoring and management purposes of network-connected devices (servers, switches, printers, routers, etc.). On Ubuntu systems, a daemon called SNMPd is available to listen and reply to SNMP requests.

To monitor another cloud Instance or elastic metal server, connect to the machine as root:

ssh root@second_cloud_instance

Update the apt repository inventory:

apt update

To display distribution information, download the distro script and make it executable:

curl -o /usr/bin/distro https://raw.githubusercontent.com/librenms/librenms-agent/master/snmp/distro
chmod +x /usr/bin/distro

Install SNMPd via apt:

apt install snmpd

Open the SNMPd configuration file in a text editor (e.g. nano):

nano /etc/snmp/snmpd.conf

Delete the content present in the default configuration file and replace it with the example below:
```
# Change RANDOMSTRINGGOESHERE to your preferred SNMP community string
com2sec readonly  123.123.123.123         RANDOMSTRINGGOESHERE
group MyROGroup v2c        readonly
view all    included  .1                               80
access MyROGroup ""      any       noauth    exact  all    none   none
syslocation "Paris, France"
syscontact Your Name <your@email.address>
#Distro Detection
extend .1.3.6.1.4.1.2021.7890.1 distro /usr/bin/distro
```
Edit the file to meet your requirements, the meaning of the different lines is explained below:
- com2sec readonly 123.123.123.123 RANDOMSTRINGGOESHERE - This line maps a security string to a community name. A security string is an access policy, an IP address limitation (replace 123.123.123.123 with the IP address of the LibreNMS Instance), and a community name (replace RANDOMSTRINGGOESHERE with the community name configured during the installation of LibreNMS).
- The line group MyROGroup v2c readonly maps a group (MyROGroup) to a security name (v2c readonly).
- The line view defines a subset of which information from the MIB is visible when polling the device via SNMP
- With the line access MyROGroup "" any noauth exact all none none access rules are tied to the group set before. In this example it means that the group MyROGroup can, in any context (""), access the data over any version of the protocol (any), without authentication (noauth), matching the exact context (exact), allowing access to all view rules (all). No write (none) or modify access (none) is permitted.
- syslocation “Paris, France” is pretty self-explanatory and specifies the geographical location of the machine.
- syscontact Your Name <your@email.address> defines the administrative contact for the machine.
- The last line is used to communicate the distribution information collected by distro via SNMP
Edit the values in the file to your needs before saving it and exiting the editor.

Restart the SNMP service:

systemctl restart snmpd.service

Add the device to LibreNMS by clicking on Devices, then Add Device in the pop-up menu from within the LibreNMS web interface.
Enter the hostname of the device, keep SNMP on, leave the values for SNMP version and Port Association Mode as preset. Enter the community name set in the file /etc/snmp/snmpd.conf as value for Community. Once all values are set, click Add Device to add the device.
LibreNMS starts polling the device and creating different graphs showing the status of the device:

For more information about the configuration options of SNMP, refer to the official documentation. You may also refer to the official LibreNMS documentation.

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