This gist is for copying the launch configurations of an existing launch configuration in AWS.

copy_launch_configurations.py

#!/usr/bin/env python3

import boto3
import argparse

def create_launch_configuration(lcargs):

  lc_dict = {}

  try:
    if lcargs.get('user_data'):
      #The file to use for userdata
      userdata = lcargs.get('user_data')
      f = open(userdata, "r")

      autoscaling_client = boto3.client('autoscaling')

      lc = autoscaling_client.describe_launch_configurations(LaunchConfigurationNames=[lcargs.get('copy_from')])
      lc_data = lc.get('LaunchConfigurations')[0]

      for key,value in lc_data.items():
        if key == 'LaunchConfigurationName':
          lc_dict[key] = value + '-' + lcargs.get('name')
        elif key == 'ImageId':
          lc_dict[key] = lcargs.get('ami_id')
        else:
          lc_dict[key] = value 

      response = autoscaling_client.create_launch_configuration(
        LaunchConfigurationName=lc_dict.get('LaunchConfigurationName'),
        ImageId=lc_dict.get('ImageId'),
        KeyName=lc_dict.get('KeyName'),
        SecurityGroups=lc_dict.get('SecurityGroups'),
        UserData=f.read(),
        InstanceType=lc_dict.get('InstanceType'),
        BlockDeviceMappings=lc_dict.get('BlockDeviceMappings'),
        InstanceMonitoring=lc_dict.get('InstanceMonitoring'),
        IamInstanceProfile=lc_dict.get('IamInstanceProfile'),
        EbsOptimized=lc_dict.get('EbsOptimized'),
       )
      f.close()

      if lcargs.get('update_ag'):
        ag_update = autoscaling_client.update_auto_scaling_group(
          AutoScalingGroupName=lcargs.get('update_ag'),
          LaunchConfigurationName=lc_dict.get('LaunchConfigurationName'),
          MinSize=1,
          MaxSize=1,
          DesiredCapacity=1,
          AvailabilityZones=[lcargs.get('azs')]
         )
    else:
      autoscaling_client = boto3.client('autoscaling')
      lc = autoscaling_client.describe_launch_configurations(LaunchConfigurationNames=[lcargs.get('copy_from')])
      lc_data = lc.get('LaunchConfigurations')[0]

      for key,value in lc_data.items():
        if key == 'LaunchConfigurationName':
          lc_dict[key] = value + '-' + lcargs.get('name')
        elif key == 'ImageId':
          lc_dict[key] = lcargs.get('ami_id')
        else:
          lc_dict[key] = value 

      response = autoscaling_client.create_launch_configuration(
        LaunchConfigurationName=lc_dict.get('LaunchConfigurationName'),
        ImageId=lc_dict.get('ImageId'),
        KeyName=lc_dict.get('KeyName'),
        SecurityGroups=lc_dict.get('SecurityGroups'),
        InstanceType=lc_dict.get('InstanceType'),
        BlockDeviceMappings=lc_dict.get('BlockDeviceMappings'),
        InstanceMonitoring=lc_dict.get('InstanceMonitoring'),
        IamInstanceProfile=lc_dict.get('IamInstanceProfile'),
        EbsOptimized=lc_dict.get('EbsOptimized'),
       )

      if lcargs.get('update_ag'):
        ag_update = autoscaling_client.update_auto_scaling_group(
          AutoScalingGroupName=lcargs.get('update_ag'),
          LaunchConfigurationName=lc_dict.get('LaunchConfigurationName'),
          MinSize=1,
          MaxSize=1,
          DesiredCapacity=1,
          AvailabilityZones=[lcargs.get('azs')]
         )
  except autoscaling_client.exceptions.AlreadyExistsFault:
    print("Launch Configuration {} exists.  Please try a new name for you launch configuration.".format(lc_dict.get('LaunchConfigurationName')))

if __name__ == "__main__":

  parser = argparse.ArgumentParser(description='Copy the Launch Configuration.', prog='copy_launch_configurations')
  subparsers = parser.add_subparsers()
  create_parser = subparsers.add_parser('create', description="Create a launch configuration", help='create launch configuration')
  create_parser.add_argument('--name', required=True, help='New launch configuration name')
  create_parser.add_argument('--copy-from', required=True, help='Launch cfg to copy')
  create_parser.add_argument('--user-data', required=False, help='File that holds userdata')
  create_parser.add_argument('--ami-id', required=True, help='The ami-id to replace in launch configuration')
  create_parser.add_argument('--update-ag', required=True, help='Update autoscaling group launch configuration')
  create_parser.add_argument('--azs', required=True, help='Availability Zone for Auto-Scaling configuration')
  args = vars(parser.parse_args())

  if 'copy_from' in args:
    create_launch_configuration(args)
  else:
   parser.print_help()