To add a simple noatime to each ext3 mount point in Puppet.

disks.rb

require 'facter'
require 'augeas'

Facter.add('fstab_missing_noatime') do
  list = []
  Augeas::open do |aug|
    aug.match("/files/etc/fstab/*[label()=~regexp('[0-9]+') and vfstype='ext3' and count(opt[.='noatime']) = 0]").each do |match|
      list.push(match)
    end
  end
  setcode do
    list.join(',')
  end
end

init.pp

class disks {

  define fstab_add_noatime( $entry = $title, $value ) {
    augeas { "insert noatime for ${entry}":
      context => $entry,
      changes => [
        "ins opt after opt[last()]",
        "set opt[last()] 'noatime'",
      ];
    }
  }

  $disks = split($::fstab_missing_noatime, ',')

  fstab_add_noatime {
    $disks:
      value => 'noatime';
  }
}