title: Starting multiple instances and wait until they are completely started using boto3
body: <p>I'm starting a bunch of <code>EC2</code> <code>Instances</code> using the following code</p>
  
  <pre><code>def start_ec2_instances(self, instanceids):
      ec2client = boto3.resource('ec2')
      response = ec2client.start_instances(InstanceIds=instanceids)
      return
  </code></pre>
  
  <p>Now it starts successfully. However I want to use <code>wait_until_running</code> method to check the status of the instances and wait until all the instances are started. </p>
  
  <p><code>wait_until_running</code> method can be issued on single instances only? How do I wait for list of instances that has been started using <code>boto3</code></p>
  
  <p>This is what I'm doing currently. But wanted to know if there are any other ways to do it in one shot</p>
  
  <pre><code>def wait_until_instance_running(self, instanceids):
      ec2 = boto3.resource('ec2')
      for instanceid in instanceids:
          instance = ec2.Instance(instanceid)
          logger.info("Check the state of instance: %s",instanceid)
          instance.wait_until_running()
      return
  </code></pre>