import os import boto3 import cfnresponse client = boto3.client('emr') def get_instance_id(event, context): response = client.list_instances( ClusterId=event['ResourceProperties']['EmrId'], InstanceGroupTypes=['MASTER'] ) instance_id = response['Instances'][0]['Ec2InstanceId'] responseData = { 'EmrMasterInstanceId': instance_id } cfnresponse.send(event, context, cfnresponse.SUCCESS, responseData)