lambda_ebs_pruner.py

#!/usr/bin/env python

import boto3

sess = boto3.Session(
  region_name="us-west-2",
)

ec2 = sess.resource('ec2')

volumes = ec2.volumes.all()

to_terminate=[]

def lambda_handler(event, context):
    for volume in volumes:
        print('Evaluating volume {0}'.format(volume.id))
        print('The number of attachments for this volume is {0}'.format(len(volume.attachments)))

        # Here's where you might add other business logic for deletion criteria
        if len(volume.attachments) == 0:
            to_terminate.append(volume)

    if len(to_terminate) == 0:
        print ("No volumes to terminate! Exiting.")
        exit()

    for volume in to_terminate:
        print('Deleting volume {0}'.format(volume.id))
        volume.delete()

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": [
                "ec2:DeleteVolume",
                "ec2:ModifyVolume",
                "ec2:DescribeVolumeStatus",
                "ec2:DescribeReplaceRootVolumeTasks",
                "ec2:DescribeVolumes",
                "ec2:DescribeVolumesModifications",
                "ec2:DescribeVolumeAttribute"
            ],
            "Resource": "*"
        }
    ]
}