Determining Amazon EC2 instance creation date/time

Question

Is it possible to determine (via boto) when a particular EC2 instance was created?

http://boto.readthedocs.org/en/latest/ref/ec2.html doesn't seem to be giving anything helpful in this case. Need to find out the creation date of a particular set of EC2 instances.

Thanks!

Answer 1

There's is no attribute called create_time for EC2 instance, only launch_time is available.

However, you can use the following Python code to know when the volume was created, which in turn gives you instance creation time (note that I'm talking about the volume attached while creating instance):

import boto3
ec2 = boto3.resource('ec2', region_name='instance_region_name')
volume = ec2.Volume('vol-id')
print volume.create_time.strftime("%Y-%m-%d %H:%M:%S")

The alternative is using custom code. When you create instances with create_instances(), you can log the launch_time for given instance along with it's instance ID and name to some place like DynamoDB so that you can retrieve the "create times" whenever you want using the instance IDs.

Answer 2

Assuming you are using an EBS-backed instance and aren't doing any fancy drive juggling, the best way to figure out the creation date of an instance is to look at the creation time of the drive's root volume. While the launch time of the instance will change every time you stop and start it, the creation time of an EBS volume is static.

Here's a quick script to find the creation time of the instance you're currently running from:

import boto
import subprocess

instance_id = subprocess.check_output(['curl', '-s', 'http://169.254.169.254/latest/meta-data/instance-id'])

conn = boto.connect_ec2()

root_device = conn.get_instance_attribute(instance_id, 'rootDeviceName')['rootDeviceName']
root_vol = conn.get_all_volumes(filters={"attachment.instance-id": instance_id, "attachment.device": root_device})[0]

print root_vol.create_time

Note that this requires the IAM Role of the instance to have ec2:DescribeInstanceAttribute and ec2:DescribeVolumes permissions