start_stop_ec2_instances_with_cloudwatch_event

start_stop_ec2_instances_with_cloudwatch_event

start_stop_ec2_instances_with_cloudwatch_event.py will toggle instance state (start/stop) when a certain tag is added, and depending upon the time of the day.

To tag the target instances, the script will look for the tag name: start-stop and it's value as yes. Tag name and it's value can be changed by altering:

paginator = paginator.paginate(Filters=[{
    'Name': 'tag:<tag-name>',
    'Values': [
        '<tag-value>'
    ]
}])

The start-stop behavior will be triggered by a CloudWatch Event source (see below). Depending upon the time of the day, function will start the instances if the triggered before noon. Likewise, for a trigger after noon, a Lambda function will stop the targeted instance.

0 8,18 * * ? *

This cron expression will trigger twice a day - once at 8:00 AM and the other at 6:00 PM. This can be used on a CloudWatch event trigger.

Feel free to play with the tag names and the time where the toggle should occur as per your use-case.

As with Lambda, this function will only list functions inside your account with the region in which this Lambda function resides. To retrieve all Lambda functions, you would need to make a describe_regions API call before creating the client and update the client for every region iteratively.

Since SDK calls could be paginated, this uses the Boto3's Paginator using Filter instances under a VPC.

Uses PrettyTable module imported as a Lambda layer.

Output

+---------------------+----------------------+--------------+
|     Instance ID     |    Security Group    |     NACL     |
+---------------------+----------------------+--------------+
| i-XXXXXXXXXXXXXXXXX | sg-XXXXXXXXXXXXXXXXX | acl-XXXXXXXX |
| i-XXXXXXXXXXXXXXXXX | sg-XXXXXXXXXXXXXXXXX | acl-XXXXXXXX |
| i-XXXXXXXXXXXXXXXXX | sg-XXXXXXXXXXXXXXXXX | acl-XXXXXXXX |
| i-XXXXXXXXXXXXXXXXX | sg-XXXXXXXXXXXXXXXXX | acl-XXXXXXXX |
+---------------------+----------------------+--------------+