For review, can you ask one of the other students to try doing this in their account?

Link: https://github.com/chirag06/auto_shutdown_ec2_instances
Steps for testing:
1) Login to your own AWS account where you have full admin privileges
2) Create two ec2 instances and add tag with key: development and value: True
3) Follow the readme file of the GitHub repository.

Suggestions:

• Under "Step 1" put "Add Tags...to skip this" after "Select AmazonEC2...and click Next" (tags configuration comes after selecting a policy
• Under "Step 2", item 3, I would recommend using a bulleted sub-list to show the 3 configurations that need to be done (function name, run-time, IAM role selection)
• Under "Step 2", should item number be "Choose Deploy" instead of "Choose Save" ?
• Add some tips on how to run the lambda function from the console just to check that it is working properly (click "Test" and don't worry about editing the boiler-plate JSON string shown)

I followed the instructions but the function did not shut down the Develop instances. The code I used was:

import boto3

def lambda_handler(event, context):
    ec2 = boto3.resource('ec2')
    filters = [{
            'Name': 'tag:Stack',
            'Values': ['Develop']
        },
        {
            'Name': 'instance-state-name', 
            'Values': ['running']
        }
    ]
    instances = ec2.instances.filter(Filters=filters)
    RunningInstances = [instance.id for instance in instances]
    for instance_id in RunningInstances:
        ec2.instances.stop(InstanceIds=[instance_id])

This worked:

import boto3
ec2 = boto3.resource('ec2')
def lambda_handler(event, context):
    filters = [{
            'Name': 'tag:Stack',
            'Values': ['Develop']
        },
        {
            'Name': 'instance-state-name', 
            'Values': ['running']
        }
    ]
    instances = ec2.instances.filter(Filters=filters)
    RunningInstances = [instance.id for instance in instances]
    for instance_id in RunningInstances:
        ec2.instances.stop(InstanceIds=[instance_id])

The only different is placement of this line:

ec2 = boto3.resource('ec2')

Request:

• Please devise cron string(s) that handle daylight savings time in the eastern US.

During the winter months, GMT is five hours ahead of eastern US (Charlotte) time. During the summer months (e.g., now), GMT is four hours ahead of eastern US time.

Hi Dr. [~aloraine],
Thank you for the suggestions. I have done the changes in the readme file. I do not know why the lambda function is not consistent with the placement of that line. Will look into it today.

Regarding the cron strings, the problem is that the dates daylight saving dates are not fixed, so it won't be possible to do that by only using cron strings. We can have one more lambda function that will be changing the Cloudwatch schedule every day according to the local time of our console. But this would incur an extra cost as cloud-watch, and lambda function would be running every day.

Thank you!

Thank you very much for the explanation. It is very helpful!

Confirming: EC2s in the loraine lab account got shut down at the proper time via cloudwatch.
Thank you Chirag Chandrahas Shetty for the very helpful code!

need to update cloudwatch for daylight savings time

[~aloraine] We can change the string in step 3 from "30 22 * * ? *" to "30 23 * * ? *".

Thank you - it is done!