Introduction

This Nagios-like plugin can be used to check the average traffic on Linux systems. It keeps track of the amount of bytes sent and received per interface with a state file. It supports thresholds and filters. The -v/--verbose option can help debug what inclusion/exclusion rules are matched.

Requirements

The script requires:

• Python 3.7 or newer
• nagiosplugin version 1.2.4 or newer
• iproute2 4.14.0 or newer
• read-write access to /tmp/ (where the state file is stored)
• sudo if --include-netns is used

Integration with Icinga

An Icinga CheckCommand can be defined with:

object CheckCommand "traffic" {
  command = [PluginDir + "/check_traffic.py"]
  arguments = {
    "--type" = "$traffic_interface_type$",
    "--name" = "$traffic_interface_name$",
    "--exclude-type" = "$traffic_interface_exclude_type$",
    "--exclude-name" = "$traffic_interface_exclude_name$",
    "--down" = {
      set_if = "$traffic_include_down_interfaces$"
    },
    "--bytes" = {
      set_if = "$traffic_use_bytes$"
    },
    "--include-netns" = {
      set_if = "$traffic_include_netns$"
    },
    "--warning" = "$traffic_warning$",
    "--critical" = "$traffic_critical$",
  }
}

Example sudoers configuration

Starting with sudo 1.9.10, it is possible to use regular expressions in sudoers files. The following example /etc/sudoers.d/icinga2-check-traffic file takes advantage of this feature. It will allow the check to work with network namespaces whose names are made up of simple alphanumeric characters and underscores, while minimizing the risk of injection.

icinga ALL=(ALL) NOPASSWD: /bin/ip ^-netns [a-zA-Z0-9_]+ -details -statistics -json link show$