Generate an Ansible inventory with a lot of hosts

generate-inventory.py

#!/usr/bin/env python

import argparse
import os
import sys
import yaml

parser = argparse.ArgumentParser()
parser.add_argument('--number', '-n', default=100)
parser.add_argument('--name', '-f', default='hosts.yml')
parser.add_argument('--force', action='store_true')

args = parser.parse_args()

filename = args.name
force = args.force
number = args.number


if os.path.isfile(filename):
    if not force:
        sys.exit('{} already exists'.format(filename))

width = len(number)
hosts = {}
for host in range(1, int(number) + 1):
    hostname = 'host_{:0{width}}'.format(host, width=width)
    hosts[hostname] = {'var1': 'somevalue'}

inventory = {'all': {'hosts': hosts}}

with open(filename, 'w') as f:
    f.write(yaml.dump(inventory))