Can I get region value for a given instance using boto 3 by passing on just private IP of ec2-instance

Question

Trying to get AWS Region for particular instance. Is that possible that by passing on only ec2 instance ip to get to know its region ?

What I tried:

import boto3
client = boto3.client('s3') # example client, could be any
client.meta.region_name

but it showing same region for all servers..

Answer 1

Unfortunately, there is no native cross-region get_instance_by_private_ip API available. But, you can do something like this

import boto3

def find_region_by_private_ip_address(ip):
    ec2 = boto3.resource('ec2', 'us-east-1')
    regions = [r['RegionName'] for r in ec2.meta.client.describe_regions()['Regions']]
    for region in regions:
        ec2 = boto3.resource('ec2', region)
        instance_iterator = ec2.instances.filter(
            Filters=[
                {
                    'Name': 'private-ip-address',
                    'Values': [
                        ip
                    ]
                },
            ]
        )
        instance_list = list(instance_iterator)
        if len(instance_list) > 0:
            return region

If performance is critical, you can do multi-threading or multi-processing to query regions in parallel.