Skip to content

Applications

Application support graphs the performance statistics of many applications.

Each application supports one or more collection methods:

  1. By direct connection to the application
  2. snmpd extend
  3. The agent.

You can add application monitoring before or after the host.

With several collection methods, enable only one.

SNMP Extend

With the snmp extend method, the application discovery module finds your monitored applications automatically. It also works on a device that is already in LibreNMS. This module is enabled by default on most *nix operating systems. On some systems, you must enable it manually.

SUDO

With SNMP extend, the scripts run as the snmpd user. This user is often unprivileged. Such a user needs sudo.

To find the need for sudo, first find the user of snmpd. Then run the extend script as that user.

Example

In this example, snmpd runs as Debian-snmp and the extend is for proxmox. These commands must run without an error:

sudo -u Debian-snmp /usr/local/bin/proxmox

If a command fails, use sudo with the extend command. For the example above, add this line to the sudoers file:

Debian-snmp ALL = NOPASSWD: /usr/local/bin/proxmox

Then add sudo to the extend command. For proxmox, the result is:

extend proxmox /usr/bin/sudo /usr/local/bin/proxmox

Restart snmpd

sudo systemctl restart snmpd

sudo service snmpd restart

JSON Return Optimization Using librenms_return_optimizer

json_app_get returns larger and more complex data from an extend. It then processes that data. The return can become large. A large return sometimes causes SNMP problems on a network.

librenms_return_optimizer corrects this problem. It takes the extend output from a pipe, compresses it with gzip, and converts it to base64. The base64 step is necessary, because net-snmp handles binary data poorly. It converts most non-printable characters to .. The base64 step adds some overhead to the gzip data. The return is still about one third of the original size for JSON items.

The change is simple. The portactivity example below:

extend portactivity /etc/snmp/extends/portactivity smtps,http,imap,imaps,postgresql,https,ldap,ldaps,nfsd,syslog-conn,ssh,matrix,gitea

Becomes this:

extend portactivity /usr/local/bin/lnms_return_optimizer -- /etc/snmp/extends/portactivity smtps,http,imap,imaps,postgresql,https,ldap,ldaps,nfsd,syslog-conn,ssh,matrix,gitea

This method needs Perl, MIME::Base64, and Gzip::Faster.

pkg install p5-MIME-Base64 p5-Gzip-Faster wget
wget https://raw.githubusercontent.com/librenms/librenms-agent/master/utils/librenms_return_optimizer -O /usr/local/bin/librenms_return_optimizer
chmod +x /usr/local/bin/librenms_return_optimizer

apt-get install zlib1g-dev cpanminus wget
cpanm Gzip::Faster
cpanm MIME::Base64
wget https://raw.githubusercontent.com/librenms/librenms-agent/master/utils/librenms_return_optimizer -O /usr/local/bin/librenms_return_optimizer
chmod +x /usr/local/bin/librenms_return_optimizer

yum install zlib-devel perl-CPAN wget
cpan Gzip::Faster
cpan MIME::Base64
wget https://raw.githubusercontent.com/librenms/librenms-agent/master/utils/librenms_return_optimizer -O /usr/local/bin/librenms_return_optimizer
chmod +x /usr/local/bin/librenms_return_optimizer

These applications are supported:

  • backupninja
  • certificate
  • chronyd
  • dhcp-stats
  • docker
  • fail2ban
  • fbsd-nfs-client
  • fbsd-nfs-server
  • gpsd
  • mailcow-postfix
  • mdadm
  • ntp-client
  • ntp-server
  • portactivity
  • powerdns
  • powermon
  • puppet-agent
  • pureftpd
  • redis
  • routinator
  • seafile
  • supervisord
  • ups-apcups
  • zfs

The following apps have extends that have native support for this, if congiured to do so.

  • suricata

Enable the application discovery module

  1. Edit the device for which you want to add this support
  2. Click on the Modules tab and enable the applications module.
  3. LibreNMS saves this change automatically. A green confirmation pop-up message.

Enable-application-module

After you enable the application module, then also enable which applications you want to monitor, in the rare case where LibreNMS does not automatically detect it.

Note: Only do this if an application was not auto-discovered by LibreNMS during discovery and polling.

Enable the application(s) to be discovered

  1. Open the device with the new application module.
  2. Click on the Applications tab and select the applications you want to monitor.
  3. LibreNMS also saves this change automatically. A green confirmation pop-up message.

Enable-applications

Agent

The unix-agent does not have a discovery module, only a poller module. That poller module is always disabled by default. It needs to need a manual enable with the agent. LibreNMS automatically enabled by the unix-agent poller module. It is better to ensure that your application is enabled for monitoring. You can check by following the steps under the SNMP Extend heading.