使用Boto轮询停止或启动的EC2实例 [英] Polling a stopping or starting EC2 instance with Boto

问题描述

我正在使用AWS，Python和 Boto库

I'm using AWS, Python, and the Boto library.

我想调用 .start（）或 .stop（） 在Boto EC2实例上，然后对其进行轮询，直到完成为止。

I'd like to invoke .start() or .stop() on a Boto EC2 instance, then "poll" it until it has completed either.

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，在最后的 while 循环中，状态似乎在待定或停止时卡住。从我的AWS控制台着重强调似乎，我可以看到实例实际上确实使其变为开始或停止。

However, in the final while loop, the state seems to get "stuck" at either "pending" or "stopping". Emphasis on "seems", as from my AWS console, I can see the instance does in fact make it to "started" or "stopped".

可以解决的办法是在 while 循环中调用 .get_all_reservations（），如下所示：

The only way I could fix this was to recall .get_all_reservations() in the while loop, like this:

    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

是否有一种调用方法，因此实例将报告ACTUAL状态？

Is there a method to call so the instance will report the ACTUAL state?

推荐答案

实例状态不会自动更新。您必须调用 update 方法，以告诉对象再次调用EC2服务并获取对象的最新状态。像这样的东西应该起作用：

The instance state does not get updated automatically. You have to call the update method to tell the object to make another round-trip call to the EC2 service and get the latest state of the object. Something like this should work:

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

要在boto3中获得相同的效果，

To achieve the same effect in boto3, something like this should work.

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

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