Skip to content

Instantly share code, notes, and snippets.

Created December 12, 2012 01:40
Show Gist options
  • Save ttddyy/4264117 to your computer and use it in GitHub Desktop.
Save ttddyy/4264117 to your computer and use it in GitHub Desktop.
a python script to display ec2 name and ip address as ssh-config or hosts file.
#! /usr/bin/env python
import argparse
import os
import sys
import boto.ec2
def parse_args():
parser = argparse.ArgumentParser(
description='Display EC2 hosts in ssh-config or hosts file format',
parser.add_argument('-k', '--aws-key', type=str,
help='Amazon EC2 Key, defaults to ENV[AWS_ACCESS_KEY_ID]')
parser.add_argument('-s', '--aws-secret', type=str,
help='Amazon EC2 Secret, defaults to ENV[AWS_SECRET_ACCESS_KEY]')
parser.add_argument('-r', '--region', type=str,
help='Amazon EC2 Region, defaults to us-east-1 or ENV[AWS_EC2_REGION]')
parser.add_argument('-t', '--tag', type=str,
default='Name', dest='name_tag',
help="Amazon EC2 Tag for instance name, defaults to 'Name'")
parser.add_argument('--prefix', type=str, default='',
help='prefix to the instance name')
parser.add_argument('--suffix', type=str, default='',
help='suffix to the instance name')
parser.add_argument('--domain', type=str, default='',
help='domain to the instance name')
parser.add_argument('--format', choices=['ssh', 'hosts'], default='ssh',
help='output format. ssh-config or hosts file style. ')
parser.add_argument('--filter', type=str, action='append', default=[],
help=('Amazon EC2 API filter to limit the result returned. '
'(Example: --filter instance-state-name=running)'))
parser.add_argument('--use-elastic-ip', action='store_true',
help='use elastic IP instead of private IP')
return parser.parse_args()
def main(opts):
aws_key = opts['aws_key']
aws_secret = opts['aws_secret']
region = opts['region']
name_tag = opts['name_tag']
prefix = opts['prefix']
suffix = opts['suffix']
domain = opts['domain']
format = opts['format']
filter = opts['filter']
use_elastic_ip = opts['use_elastic_ip']
filters = dict([f.split('=', 1) for f in filter])
if domain and not domain.startswith('.'):
domain = '.' + domain
ip_addr_attr = 'ip_address' if use_elastic_ip else 'private_ip_address'
# validation
if not aws_key or not aws_secret:
if not aws_key:
print >> sys.stderr,\
"AWS_ACCESS_KEY_ID not set in environment and not",\
"specified by -k AWS_KEY or --aws-key AWS_KEY"
if not aws_secret:
print >> sys.stderr,\
"AWS_SECRET_ACCESS_KEY not set in envoronment and not",\
"specified by -s AWS_SECRET or --aws-secret AWS_SECRET"
region = region and boto.ec2.get_region(region,
conn = boto.ec2.connection.EC2Connection(aws_key, aws_secret,
# list of (instance_name, ip_address)
instances = get_ec2_instances(conn, name_tag, ip_addr_attr, filters)
# sort by name
instances = sorted(instances)
# print out
print_fn = print_ssh_config if format == 'ssh' else print_hosts
print_fn(instances, prefix, suffix, domain)
def get_ec2_instances(conn, name_tag, ip_addr_attr, filters):
instances = [] # (instance_name, ip_address)
reservations = conn.get_all_instances(filters=filters)
for reservation in reservations:
for instance in reservation.instances:
instance_name = instance.tags.get(name_tag)
ip_address = getattr(instance, ip_addr_attr)
if instance_name and ip_address:
pair = (instance_name, ip_address)
return instances
def print_ssh_config(instances, prefix, suffix, domain):
""" Print out as ssh-config file format """
for instance_name, ip_address in instances:
instance_name = prefix + instance_name + suffix + domain
# double quote if name contains space
instance_name = '"{0}"'.format(
instance_name) if ' ' in instance_name else instance_name
print "Host %s" % instance_name
print "Hostname %s" % ip_address
print ""
def print_hosts(instances, prefix, suffix, domain):
""" Print out as hosts file format """
for instance_name, ip_address in instances:
if ' ' in instance_name:
continue # skip if name contains space.
instance_name = prefix + instance_name + suffix + domain
print "%s\t%s" % (ip_address, instance_name)
if __name__ == '__main__':
args = vars(parse_args())
Copy link

ttddyy commented Dec 12, 2012

Usage sample:

# display entries as ssh-config file format
./ec2-printconfig -k <aws_key> -s <aws_secret> -r us-west-2

# display entries as hosts file format
./ec2-printconfig --format hosts

# add prefix "my-" to instance name. (ex: my-foo, my-bar, ...)
./ec2-printconfig --prefix my-

# add domain "" to instance name. (ex:,, ...)
./ec2-printconfig --domain

# use elastic IP instead of private IP
./ec2-printconfig --use-elastic-ip

# filter instances. (ex: only running and monitored instances. )
./ec2-printconfig --filter monitoring-state=enabled --filter instance-state-name=running

# specify tag for ec2 instance name. (ex: assume there is "alias" tag)
./ec2-printconfig -t alias

Copy link

ttddyy commented Dec 12, 2012

Copy link

teambob commented Jun 22, 2017


I have modified this script and used it myself. I was wondering what license are you happy to use? Would GPLv2 be ok?

My fork is publicly accessible, so please feel free to check it out.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment