librenms

A Puppet module for managing LibreNMS

Usage

The Puppet manifest used by Vagrant (vagrant/librenms.pp) shows how to

• Setup LibreNMS (install, configuration, permissions, ACLs, users, etc.)
• Use puppetlabs-mysql to configure database, user and grants
• Setup snmpd and create and SNMPv3 user
• Add the LibreNMS node to LibreNMS

The manifest used by Vagrant uses two optional features of this module that

• Install the required php packages
• Configure Apache to serve LibreNMS on port 80 (http)

Hints for production

To import a node into LibreNMS using exported resources:

class { '::snmpd':
  allow_address_ipv4 => '10.0.0.0',
  allow_netmask_ipv4 => '8',
  users              => { 'monitor' => { 'pass' => 'my-password' } },
}

class { '::librenms::device':
  proto => 'v3',
  user  => 'monitor',
  pass  => 'my_password',
}

To use SNMPv2 instead:

class { '::librenms::device':
  proto      => 'v2',
  community  => 'public',
}

Create and remove devices using LibreNMS v0 API:

librenms_device { 'snmpv3.example.org':
  ensure     => 'present',
  url        => 'https://librenms.example.org/api/v0',
  auth_token => '0123456789abcde0123456789abcded0',
  snmpver    => 'v3',
  authlevel  => 'noAuthNoPriv',
  authname   => 'snmpuser',
  authpass   => 'secret',
  authalgo   => 'sha',
  cryptopass => 'secret',
  cryptoalgo => 'aes',
}

librenms_device { 'snmpv2.example.org':
  ensure     => 'present',
  url        => 'https://librenms.example.org/api/v0',
  auth_token => '0123456789abcde0123456789abcded0',
  snmpver    => 'v2c',
  community  => 'public',
}

# Ensure that a decommissioned node is not present in LibreNMS
librenms_device { 'decommissioned.example.org':
  ensure => 'absent',
}

The provider uses the "force_add" parameter to ensure that nodes that are (temporarily) inaccessible (e.g. being provisioned) are added correctly.

You can also manage services using the LibreNMS v0 API:

librenms_service { 'http-on-librenms':
  ensure     => 'present',
  url        => 'http://librenms.example.org/api/v0',
  auth_token => '0123456789abcde0123456789abcded0',
  hostname   => 'librenms.example.org',
  type       => 'http',
  ip         => 'librenms.example.org',
  param      => 'C 50 --sni -S',
}

There are couple of caveats regarding service management:

• The "desc" parameter, which defaults to the resource title, is used as an identifier at the LibreNMS. This is because it is the only property which is purely informational. You can use this to import existing resources to Puppet. If multiple services matching the same "desc" on the same device are found then Puppet will bail out and ask you to resolve the situation.
• No verification is done on any of the parameters at Puppet or LibreNMS end except for basic data type validation. For example you can change "type" from "http" (valid) to "https" (invalid) without any errors or warnings.

To create CustomOID checks use the librenms_customoid type. Below an example of how to use this with net-snmp-systemd-service-status:

$service = 'sshd'

# Convert human-readable (ASCII) name to an OID
$oid = librenms::name_to_oid($service)
$descr = "${service} on ${::fqdn}"

@@librenms_customoid { $descr:
  ensure   => present,
  
  # Database username and password: there's no API support for manipulating
  # CustomOIDs
  username => 'librenms',
  password => 'secret',
  
  # Bind this CustomOID to hostname that matches value of $::fqdn fact
  hostname => $::fqdn,
  
  # Alternatively use sysName instead for the mapping
  # sysName   => $::hostname,
   
  # Turn on alerting for this CustomOID.
  alert    => 1,
  
  # Human readable description
  descr    => $descr,
  
  # The OID, which matches the service name converted to ASCII.
  oid      => $oid,
  
  # Send critical alert if the service is not up. We get 0 if it is up, 1
  # otherwise.
  limit    => 1,
  
  # Collect using tags
  tag      => 'default'
}

Then just realize the exported resources on the LibreNMS server:

Librenms_customoid <<| tag == 'default' |>>

See lib/puppet/type/librenms_customoid.rb for documentation of all the available parameters.

Testing with Vagrant

If you have Vagrant and virtualbox installed then setting up LibreNMS test instance from scratch should be as easy as:

$ vagrant up

LibreNMS UI can be reached via

• https://192.168.152.10 (librenms)
• https://192.168.152.11 (librenms-focal)

Username is "admin" and password is "vagrant". The instance adds itself to LibreNMS, so you should see one device, "librenms.vagrant.example.lan" under devices.

If you want to use snmpwalk note that the username is "librenms" and password is "vagrant123".