How to get EC2 ID and Private IP from EC2 Autoscaling Group using AWS CDK

Question

How can I get the instance ID and private IP for EC2 instance deployed with AutoscalingGroup (AWS CDK Python) ?

The AutoscalingGroup Construct is like this:

from aws_cdk import (
    core,
    aws_ec2,
    aws_autoscaling
)

autoscaling_group = aws_autoscaling.AutoScalingGroup(
            self,
            id="AutoscalingGroup",
            instance_type=aws_ec2.InstanceType('m5.xlarge'),
            machine_image=aws_ec2.MachineImage.latest_amazon_linux(),
            vpc=Myvpc,
            vpc_subnets=aws_ec2.SubnetSelection(subnet_type=aws_ec2.SubnetType.PUBLIC),
            associate_public_ip_address=True,
            desired_capacity=1,
            key_name='MySSHKey'
        )

Thank you very much.

Answer 1

You can retrieve them using boto3.

Here is an example to get them only for the running instances :

ec2_res = boto3.resource('ec2')

instances = ec2_res.instances.filter(
    Filters=[
        {'Name': 'instance-state-name', 'Values': ['running']}
    ]
)

for instance in instances:
   print(instance.id, instance.instance_type, instance.private_ip_address)

You can check the doc here for available parameters and here for the boto3 call.

If you want to filter on a specific name, you have to check in the tags of the instances:

for instance in instances:
    for tag in instance.tags:
        if (tag.get('Key') == 'Name') and (tag.get('Value') == '<The name of your instance>'):
            print(instance.id, instance.instance_type, instance.private_ip_address)