Terminate_ASG.py

import boto3
import time
import datetime
print "Function Start Time: "+ str(datetime.datetime.now())
Region='us-east-1'
ASG_Name='awseb-e-3rreanw3r3-stack-AWSEBAutoScalingGroup-C20XEFG034MN'
Draining_Time='20'
ELB_Name='awseb-e-3-AWSEBLoa-PPG010DUGCPK'
ASG_Instance_Count=3
asg_client = boto3.client('autoscaling',region_name=Region)
elb_client = boto3.client('elb',region_name=Region)
ec2_client = boto3.client('ec2',region_name=Region)
waiter = ec2_client.get_waiter('instance_terminated')
asg_response = asg_client.describe_auto_scaling_groups(AutoScalingGroupNames=[ASG_Name])
len(asg_response['AutoScalingGroups'][0]['Instances'])
for Instance in range(len(asg_response['AutoScalingGroups'][0]['Instances'])):
	Instance_ID=asg_response['AutoScalingGroups'][0]['Instances'][Instance]['InstanceId']
	print "Detaching this Instance from ASG"
	asg_client.detach_instances(InstanceIds=[Instance_ID],AutoScalingGroupName=ASG_Name,ShouldDecrementDesiredCapacity=False)
	print "Deregistering the Instance - "+ Instance_ID
	elb_client.deregister_instances_from_load_balancer(LoadBalancerName=ELB_Name,Instances=[{'InstanceId': Instance_ID}])
	print "Wait till the Instance is Deregistered"
	time.sleep(int(Draining_Time))
	print "Terminating the Instance - "+ Instance_ID
	ec2_terminate = ec2_client.terminate_instances(InstanceIds=[Instance_ID])
	waiter.wait(InstanceIds=[Instance_ID])
	print "Terminated Instance Successfully"
	if Instance < (ASG_Instance_Count-1):
		print "Wait for 2 minutes before terminating another instance"
		time.sleep(120)
print "Function End Time: "+ str(datetime.datetime.now())