Какую метрику CloudWatch выбрать?

import boto.ec2.cloudwatch
import sys
import os
import boto.sns



os.environ['AWS_KEY'] = "xxxxx"
os.environ['AWS_SECRET'] = "xxxxx"
os.environ['AWS_REGION'] = "us-west-2"

def create_status_alarm(instance_id):



    ec2_conn = boto.ec2.connect_to_region(
    	os.environ['AWS_REGION'],
        aws_access_key_id=os.environ['AWS_KEY'],
        aws_secret_access_key=os.environ['AWS_SECRET'])

    cloudwatch_conn = boto.ec2.cloudwatch.connect_to_region(
        os.environ['AWS_REGION'],
        aws_access_key_id=os.environ['AWS_KEY'],
        aws_secret_access_key=os.environ['AWS_SECRET'])

    reservations = ec2_conn.get_all_instances(filters = {'instance-id': instance_id})

    if reservations and reservations[0].instances:
        instance = reservations[0].instances[0]
        instance_name = instance.tags['Name']
    else:
        print "Invalid instance-id!"
        sys.exit(1)
    sns_conn = boto.sns.SNSConnection(aws_access_key_id = os.environ['AWS_KEY'], aws_secret_access_key = os.environ['AWS_SECRET'], region=boto.regioninfo.RegionInfo(name=os.environ['AWS_REGION'], endpoint='sns.%s.amazonaws.com' % os.environ['AWS_REGION']))
    sns_topic = sns_conn.create_topic('qweqwe2')
    topic_arn = sns_topic["CreateTopicResponse"]\
                      ["CreateTopicResult"]\
                      ["TopicArn"]
    subscription = sns_conn.subscribe(topic_arn, "email", "xxxxxx@gmail.com")
    print topic_arn

    alarm = boto.ec2.cloudwatch.alarm.MetricAlarm(
        connection = cloudwatch_conn,
        name = instance_name + "checkfail2",
        metric = 'StatusCheckFailed',
        namespace = 'AWS/EC2',
        statistic = 'Minimum',
        comparison = '>',
        description = 'status check for %s %s' % (instance_id, instance_name),
        threshold = 0,
        period = 60,
        evaluation_periods = 2,
        dimensions = {'InstanceId':instance_id},
        alarm_actions = topic_arn,
        ok_actions = topic_arn,
        insufficient_data_actions = topic_arn)
    cloudwatch_conn.put_metric_alarm(alarm)


if __name__ == '__main__':
    if len(sys.argv) < 2:
        print "Usage: create_status_alarm.py <instanceid>"
        sys.exit(2)
    create_status_alarm(sys.argv[1])