Lambda function to automatically stop an instance

Question

I have used the below Lambda code to auto stop instances, with Instance IDs specified. I would like to target all the running instances instead of specific ones, hence please advise how can I achieve this. Please note this works successfully for the Instance IDs specified.  The code is below:

import boto3
region = 'eu-west-2'

ec2 = boto3.client('ec2', region_name=region)
instances = ['i-02639vfrge55c5ad2','i-03tyho9cffe4aee0']

def lambda_handler(event, context):
    ec2.stop_instances(InstanceIds=instances)
    print('stopped your instances: ' + str(instances))

Accepted Answer

There is also a Solution for stopping instances on a schedule if that is what you are working on. [Instance Scheduler on AWS](https://aws.amazon.com/solutions/implementations/instance-scheduler/)

Answer

There is no single API to stop all the running instances. You need to get the list of running instance using the [`describe_instances`](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#EC2.Client.describe_instances) API. You can use the `instance-state-name` filter to get only the `running` instances. Once you have the result, you can extract the instance IDs, place them in an array and call the `stop_instances` API as you did before.

Lambda function to automatically stop an instance

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