check_df.rb

#!/usr/local/bin/ruby

# これは最初に書いた古いバージョン。
# 現在運用中の新しいやつはここ。
# https://github.com/pooza/ginseng/blob/master/bin/nagios/check-df.rb

require 'net/ssh'
require 'timeout'
require 'optparse'

options = ARGV.getopts('H:u:', 'key:', 'mountpoint:', 'seconds:')
options['key'] ||= '~/.ssh/id_rsa'
options['mountpoint'] ||= '/'
options['seconds'] ||= 20

begin
  Timeout.timeout(options['seconds']) do
    Net::SSH.start(options['H'], options['u'], :keys => [options['key']]) do |ssh|
      result = ssh.exec!("df #{options['mountpoint']}").each_line.to_a[1].split(/\s+/)
      usage = result[4].sub!(/%$/, '').to_i
      if 90 < usage
        print "NG #{usage}%"
        exit 2
      elsif 80 < usage
        print "WARN #{usage}%"
        exit 1
      end
      print "OK #{usage}%"
    end
  end
rescue => e
  print "NG #{e.class} #{e.message}"
  exit 2
end