Script for resizing an EC2 instance, and restarting it. Prints the new IP at the end.

ec2resize.py

#!/usr/bin/env python3
import boto3
import argparse
from time import sleep

def getInstanceIP(id):
	resp = client.describe_instances(InstanceIds=[args.ec2])
	try:
		return resp['Reservations'][0]['Instances'][0]['PublicIpAddress']
	except:
		print("Unable to fetch IP. Please use AWS Console")
		return ""

def getInstanceInfo(id):
	#first show the instance info. only going to pickup the first instance.
	resp = client.describe_instances(InstanceIds=[args.ec2])
	for res in resp['Reservations'][0]['Instances']:
		try:
			if (res['Tags'][0]['Key'] == 'Name'):
				print("Instance Name: " + res['Tags'][0]['Value'])
			print("Instance Current Size: " + res['InstanceType'])
		except:
			print("some key error")

parser = argparse.ArgumentParser()
parser.add_argument("ec2", help="ec2 instance id")
parser.add_argument("size", help="size to change to")
args = parser.parse_args()

client = boto3.client('ec2')

# Insert your Instance ID here
my_instance = args.ec2

#print inst info first
getInstanceInfo(my_instance)

reply = str(input("Do you want to continue with the operation?(y/[n]):")).lower().strip()
if (reply[0] is not 'y'):
	print("aborting")
	exit()

# Stop the instance
print("Stopping existing instance...")
client.stop_instances(InstanceIds=[my_instance])
waiter=client.get_waiter('instance_stopped')
waiter.wait(InstanceIds=[my_instance])
print("Changing instance type to : " + args.size)
# Change the instance type
client.modify_instance_attribute(InstanceId=my_instance, Attribute='instanceType', Value=args.size)

# Start the instance
print("starting instance..")
client.start_instances(InstanceIds=[my_instance])
# sleep 10 secs to get ip
sleep(10)
print("New IP is : " + getInstanceIP(my_instance))