Puppet Custom Fact - Host Interface

I've found this simple custom fact extremely useful. It basically does a netstat -rn and grabs the default interface that has the gateway. I've tested it on FreeBSD, Redhat, and Ubuntu, it probably works on other platforms.

To install this module on your puppet master

mkdir -p /etc/puppet/modules/hostint/lib/facter

Copy the following code and place it in the file "/etc/puppet/modules/hostint/lib/facter/hostint.rb"

require 'facter'
Facter.add(:hostint) do
  confine :kernel => %w{FreeBSD}
  setcode do
    Facter::Util::Resolution.exec("netstat -f inet -rn | awk '$1==\"default\" { print $6 }'")
  end
end

Facter.add(:hostint) do
  confine :kernel => %w{Linux}
  setcode do
    Facter::Util::Resolution.exec("netstat -rn | awk '$1==\"0.0.0.0\" { print $8 }'")
  end
end

Ensure you have pluginsync enabled in your nodes puppet.conf

pluginsync = true

Now you are free to use this fact name in any module/manifest

<%= hostint %>

You can also download the module on the puppet forge http://forge.puppetlabs.com/panaman/hostint/0.0.1
Or install it straight from your puppet master

puppet module install panaman-hostint