How to obtain current instance ID from boto3?

Question

Is there an equivalent of

curl http://169.254.169.254/latest/meta-data/instance-id

with boto3 to obtain the current running instance instance-id in python?

Answer 1

In fact, scrap that answer. All you need is ec2-metadata https://github.com/adamchainz/ec2-metadata

pip3 install ec2-metadata

from ec2_metadata import ec2_metadata
print(ec2_metadata.instance_id)

Answer 2

I'm late to the party but after coming across this question and being disappointed that there was no satisfactory boto3 based answer to getting current ec2's instanceid, I set out to fix that.

You get the hostname (which is also the PrivateDnsName) using socket and feed that into a filter on a query to describe_instances and used that to fetch the InstanceId.

import socket
import boto3


session = boto3.Session(region_name="eu-west-1")
ec2_client = session.client('ec2')

hostname = socket.gethostname()

filters = [ {'Name': 'private-dns-name',
            'Values': [ hostname ]}
           ]

response = ec2_client.describe_instances(Filters=filters)["Reservations"]
instanceid = response[0]['Instances'][0]['InstanceId']
print(instanceid)

Your instance will need EC2 read privileges granted via IAM. Policy AmazonEC2ReadOnlyAccess granted to your instance role would work for that.

Answer 3

There is still no boto3 api to do it. But if your current instance is Linux system, then you can use the following python3 code to get the instance_id:

import subprocess

cmd='''set -o pipefail && sudo grep instance-id /run/cloud-init/instance-data.json | head -1 | sed 's/.*\"i-/i-/g' | sed 's/\",//g\''''    
status, instance_id = subprocess.getstatusoutput(cmd)
print(status, instance_id)