EC2のメモリ、ディスクの使用率をCloudWatchのカスタムメトリクスに追加するcronスクリプト

config.rb

require 'aws-sdk'

$config_file = File.join(File.dirname(__FILE__), "../../config/aws/aws.yml")
$config = YAML.load(File.read($config_file))

AWS.config(
  access_key_id:     $config['access_key_id'],
  secret_access_key: $config['secret_access_key'],
  region:            $config['region']
)

mon_put_data_ec2.rb

#!/usr/bin/env ruby
# OSの監視情報をCloudWatchのカスタムメトリクスに追加するスクリプト
#
# 追加する項目
#   - メモリ使用率
#   - ディスク利用率
#     - /     : 標準EBSボリューム
#     - /data : 追加EBSボリューム
# 各EC2インスタンス上のcronで5分ごとに実行
#   */5 * * * * ec2-user /home/ec2-user/bin/mon_put_data_ec2.rb 

require File.expand_path(File.dirname(__FILE__) + '/config')
require 'net/http'

NAMESPACE = 'Custom/EC2'

def mem_usage
  meminfo = {}
  File.open('/proc/meminfo').each do |line|
    line =~ /^(.*?):\s+(\d+)/ or next;
    meminfo[$1] = $2.to_i * 1024
  end

  total = meminfo['MemTotal']
  avail = meminfo['MemFree'] + meminfo['Cached'] + meminfo['Buffers']

  100.0 * ( total - avail ) / total
end

def disk_usage(path)
  df = "/bin/df -k -l -P #{path} | tail -n 1"
  total, used = `#{df}`.chomp.split(/\s+/).values_at(1, 2)

  100 * ( used.to_f / total.to_f )
end

instance_id = Net::HTTP.get('169.254.169.254', '/latest/meta-data/instance-id')
dimensions = [ { name: 'InstanceId', value: instance_id } ]
metric_data = [
  { metric_name: 'MemoryUsage',    value: mem_usage },
  { metric_name: 'DiskUsage_root', value: disk_usage('/') },
  { metric_name: 'DiskUsage_data', value: disk_usage('/data') },
]
metric_data.each do |m|
  m[:dimensions] = dimensions
  m[:unit] = 'Percent'
end

cw = AWS::CloudWatch.new
cw.put_metric_data( namespace: NAMESPACE, metric_data: metric_data )

set_alerm_ec2.rb

#!/usr/bin/env ruby
# EC2インスタンスにアラームを設定するスクリプト
# ※事前にアラート送信先となるSNSトピックを作成しておくこと

require File.expand_path(File.dirname(__FILE__) + '/config')

if ARGV.size != 1
  puts "usage: #{$0} <hostname>"
  exit 1
end

hostname = ARGV.shift
ec2 = AWS::EC2.new
instance_id = ec2.tags.filter('value', hostname).first.resource.id

cw_config = [
  {
    namespace: 'AWS/EC2',
    metric_name: 'StatusCheckFailed',
    threshold: 0,
    comparison_operator: 'GreaterThanThreshold'
  },
  {
    namespace: 'AWS/EC2',
    metric_name: 'CPUUtilization',
    threshold: 80,
    comparison_operator: 'GreaterThanThreshold'
  },
  {
    namespace: 'Custom/EC2',
    metric_name: 'MemoryUsage',
    threshold: 80,
    comparison_operator: 'GreaterThanThreshold'
  },
  {
    namespace: 'Custom/EC2',
    metric_name: 'DiskUsage_root',
    threshold: 80,
    comparison_operator: 'GreaterThanThreshold'
  },
  {
    namespace: 'Custom/EC2',
    metric_name: 'DiskUsage_data',
    threshold: 80,
    comparison_operator: 'GreaterThanThreshold'
  },
]

cw = AWS::CloudWatch.new
cw_config.each do |config|
  alert_name = [ hostname, config[:namespace], config[:metric_name] ].join('-')
  cw.alarms.create( alert_name,
    namespace:           config[:namespace],
    metric_name:         config[:metric_name],
    threshold:           config[:threshold],
    comparison_operator: config[:comparison_operator],
    statistic:           'Average', 
    period:              300, 
    dimensions:          [ { name: 'InstanceId', value: instance_id } ],
    evaluation_periods:  1,
    ok_actions:                $config['cloudwatch']['actions'],
    alarm_actions:             $config['cloudwatch']['actions'],
    insufficient_data_actions: $config['cloudwatch']['actions'],
  )
end

aws.ymlの中身が知りたいです。actionの記載もあるのですか？