使用Boto轮询停止或启动EC2实例

Question

我正在使用AWS,Python和Boto库.

我想调用.start()或.stop()在Boto EC2实例上,然后"轮询"它直到它完成.

import boto.ec2

credentials = {
  'aws_access_key_id': 'yadayada',
  'aws_secret_access_key': 'rigamarole',
  }

def toggle_instance_state():
    conn = boto.ec2.connect_to_region("us-east-1", **credentials)
    reservations = conn.get_all_reservations()
    instance = reservations[0].instances[0]
    state = instance.state
    if state == 'stopped':
        instance.start()
    elif state == 'running':
        instance.stop()
    state = instance.state
    while state not in ('running', 'stopped'):
        sleep(5)
        state = instance.state
        print " state:", state

但是,在最后一个while循环中,状态似乎"停滞"在"待定"或"停止"状态.强调"似乎",从我的AWS控制台,我可以看到实例确实使它"开始"或"停止".

我能解决这个问题的唯一方法是.get_all_reservations()在while循环中回忆起来,就像这样:

    while state not in ('running', 'stopped'):
        sleep(5)
        # added this line:
        instance = conn.get_all_reservations()[0].instances[0]
        state = instance.state
        print " state:", state

是否有一种方法可以调用,以便instance报告实际状态？

Answer 1

实例状态不会自动更新.您必须调用该update方法来告诉对象对EC2服务进行另一次往返调用并获取对象的最新状态.这样的事情应该有效:

while instance.state not in ('running', 'stopped'):
    sleep(5)
    instance.update()

为了在boto3中实现相同的效果,这样的事情应该有效.

import boto3
ec2 = boto3.resource('ec2')
instance = ec2.Instance('i-1234567890123456')
while instance.state['Name'] not in ('running', 'stopped'):
    sleep(5)
    instance.load()

Answer 2

Python Boto3 中的 wait_until_running 函数似乎是我会使用的。

http://boto3.readthedocs.io/en/latest/reference/services/ec2.html#EC2.Instance.wait_until_running