Starting multiple instances and wait until they are completely started using boto3

Question

I'm starting a bunch of EC2 Instances using the following code

def start_ec2_instances(self, instanceids):
    ec2client = boto3.resource('ec2')
    response = ec2client.start_instances(InstanceIds=instanceids)
    return

Now it starts successfully. However I want to use wait_until_running method to check the status of the instances and wait until all the instances are started.

wait_until_running method can be issued on single instances only? How do I wait for list of instances that has been started using boto3

This is what I'm doing currently. But wanted to know if there are any other ways to do it in one shot

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

Answer 1

Use

• Wait until instance is running or
• Wait until a successful state is reached

Try this:

ec2 = boto3.client('ec2')
start_ec2_instances(instanceids)
waiter = ec2.get_waiter('instance_running')
waiter.wait(InstanceIds=instanceids)

The waiter function polls every 15 seconds until a successful state is reached. An error is returned after 40 failed checks.

Answer 2

You can use EC2 client's Waiter.wait call to pass an array of EC2 instance Ids.

http://boto3.readthedocs.io/en/latest/reference/services/ec2.html#EC2.Waiter.InstanceRunning