Get running instances behind ELB by 'Release' tag

getInstancesByRelease.py

#!/usr/bin/env python

import argparse

import boto.ec2.elb
import boto.ec2

parser = argparse.ArgumentParser(description="Get ELB instances by release tag")
parser.add_argument("-region", "--region",    
                   metavar="region",    
                   dest="region",    
                   required=True,
                   help="AWS Region")
parser.add_argument("-release", "--release",
                   metavar="release",
                   dest="release",
                   required=True,
                   help="Release")
args = parser.parse_args()

ec2conn = boto.ec2.connect_to_region(args.region)

print "Filtering running instances for Release tag => " + args.release

reservations = ec2conn.get_all_instances(filters={"tag:Release": args.release})
instances = [i for r in reservations for i in r.instances]
addresses = [i.private_ip_address for r in reservations for i in r.instances]

instance_ids = []

for instance, address in zip(instances, addresses):
    print instance, address