How do I set an alarm to terminate an EC2 instance using boto?

问题

I have been unable to find a simple example which shows me how to use boto to terminate an Amazon EC2 instance using an alarm (without using AutoScaling). I want to terminate the specific instance that has a CPU usage less than 1% for 10 minutes.

Here is what I've tried so far:

import boto.ec2
import boto.ec2.cloudwatch
from boto.ec2.cloudwatch import MetricAlarm

conn = boto.ec2.connect_to_region("us-east-1", aws_access_key_id=ACCESS_KEY, aws_secret_access_key=SECRET_KEY)
cw = boto.ec2.cloudwatch.connect_to_region("us-east-1", aws_access_key_id=ACCESS_KEY, aws_secret_access_key=SECRET_KEY)

reservations = conn.get_all_instances()
for r in reservations:
    for inst in r.instances:
        alarm = boto.ec2.cloudwatch.MetricAlarm(name='TestAlarm', description='This is a test alarm.', namespace='AWS/EC2', metric='CPUUtilization', statistic='Average', comparison='<=', threshold=1, period=300, evaluation_periods=2, dimensions={'InstanceId':[inst.id]}, alarm_actions=['arn:aws:automate:us-east-1:ec2:terminate'])
        cw.put_metric_alarm(alarm)

Unfortunately it gives me this error:

dimensions={'InstanceId':[inst.id]}, alarm_actions=['arn:aws:automate:us-east-1:ec2:terminate']) TypeError: init() got an unexpected keyword argument 'alarm_actions'

I'm sure it's something simple I'm missing.

Also, I am not using CloudFormation, so I cannot use the AutoScaling feature. This is because I don't want the alarm to use a metric across the entire group, rather only for a specific instance, and only terminate that specific instance (not any instance in that group).

Thanks in advance for your help!

回答1:

The alarm actions are not passed through dimensions but rather added as an attribute to the MetricAlarm object that you are using. In your code you need to do the following:

alarm = boto.ec2.cloudwatch.MetricAlarm(name='TestAlarm', description='This is a test alarm.', namespace='AWS/EC2', metric='CPUUtilization', statistic='Average', comparison='<=', threshold=1, period=300, evaluation_periods=2, dimensions={'InstanceId':[inst.id]})
alarm.add_alarm_action('arn:aws:automate:us-east-1:ec2:terminate')
cw.put_metric_alarm(alarm)

You can also see in the boto documentation here:

http://docs.pythonboto.org/en/latest/ref/cloudwatch.html#module-boto.ec2.cloudwatch.alarm

来源：https://stackoverflow.com/questions/21863805/how-do-i-set-an-alarm-to-terminate-an-ec2-instance-using-boto