Any event listener in aws-python once an instance is started

Question

I want to start an ec2 instances depends on the state of other ec2 instances through lambda functions.For example, Webserver ec2 instances has to start once Database instances will start.As of now i am using the sleep method of time component but thinking that there should be a way to do my requirement and it's not good for product having a 1-2 minutes of downtime to start just ec2 instances.

import boto3
import time
region = 'us-west-1'
db_instances = ['i-12345cb6de4f78g9h', 'i-08ce9b2d7eccf6d26']
web_instances = ['i-12345cb6de4f78h8g', 'i-08ce9b2d7eccf6548']
ec2 = boto3.client('ec2', region_name=region)

def lambda_handler(event, context):
    ec2.start_instances(InstanceIds=db_instances)
    print('started your instances: ' + str(db_instances))
    time.sleep(60)
    ec2.start_instances(InstanceIds=web_instances)
    print('started your instances: ' + str(web_instances))

Suggestions are welcome and thanks.

Varun Vembar · Accepted Answer · 2019-11-13 12:42:21Z

1

Check the instance states

db_1 = ec2.Instance(id1).state
db_2 = ec2.Instance(id2).state

Set some flag which becomes True only if both instances are running

check_flag = True
if db_1 == 'running' and db_2 == 'running':
    check_flag = False

Combine both , and add the web startup snippet

check_flag = True
while check_flag:
    db_1 = ec2.Instance(id1).state
    db_2 = ec2.Instance(id2).state
    if db_1 == 'running' and db_2 == 'running':
        check_flag = False
ec2.start_instances(InstanceIds=web_instances)

edited Nov 13, 2019 at 12:42

answered Nov 12, 2019 at 13:49

Varun Vembar

3586 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Any event listener in aws-python once an instance is started

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related