AWS Cost Cleanup

Automate the identification and removal of unused AWS resources to eliminate waste.

When to Use This Skill

Use this skill when you need to automatically clean up unused AWS resources to reduce costs and eliminate waste.

Automated Cleanup Targets

Storage

• Unattached EBS volumes
• Old EBS snapshots (>90 days)
• Incomplete multipart S3 uploads
• Old S3 versions in versioned buckets

Compute

• Stopped EC2 instances (>30 days)
• Unused AMIs and associated snapshots
• Unused Elastic IPs

Networking

• Unused Elastic Load Balancers
• Unused NAT Gateways
• Orphaned ENIs

Cleanup Scripts

Safe Cleanup (Dry-Run First)

#!/bin/bash
# cleanup-unused-ebs.sh

echo "Finding unattached EBS volumes..."
VOLUMES=$(aws ec2 describe-volumes \
  --filters Name=status,Values=available \
  --query 'Volumes[*].VolumeId' \
  --output text)

for vol in $VOLUMES; do
  echo "Would delete: $vol"
  # Uncomment to actually delete:
  # aws ec2 delete-volume --volume-id $vol
done

#!/bin/bash
# cleanup-old-snapshots.sh

CUTOFF_DATE=$(date -d '90 days ago' --iso-8601)

aws ec2 describe-snapshots --owner-ids self \
  --query "Snapshots[?StartTime<='$CUTOFF_DATE'].[SnapshotId,StartTime,VolumeSize]" \
  --output text | while read snap_id start_time size; do
  
  echo "Snapshot: $snap_id (Created: $start_time, Size: ${size}GB)"
  # Uncomment to delete:
  # aws ec2 delete-snapshot --snapshot-id $snap_id
done

#!/bin/bash
# release-unused-eips.sh

aws ec2 describe-addresses \
  --query 'Addresses[?AssociationId==null].[AllocationId,PublicIp]' \
  --output text | while read alloc_id public_ip; do
  
  echo "Would release: $public_ip ($alloc_id)"
  # Uncomment to release:
  # aws ec2 release-address --allocation-id $alloc_id
done

S3 Lifecycle Automation

# Prepare a lifecycle proposal. This replaces bucket lifecycle configuration;
# retrieve/merge existing rules and scope the prefix before any authorized apply.
cat > lifecycle-policy.json <<EOF
{
  "Rules": [
    {
      "Id": "Archive old objects",
      "Status": "Enabled",
      "Transitions": [
        {
          "Days": 90,
          "StorageClass": "STANDARD_IA"
        },
        {
          "Days": 180,
          "StorageClass": "GLACIER"
        }
      ],
      "NoncurrentVersionExpiration": {
        "NoncurrentDays": 30
      },
      "AbortIncompleteMultipartUpload": {
        "DaysAfterInitiation": 7
      }
    }
  ]
}
EOF

# After explicit review only, apply the merged policy to the confirmed bucket.

Cost Impact Calculator

#!/usr/bin/env python3
# calculate-savings.py

import boto3
from datetime import datetime, timedelta

ec2 = boto3.client('ec2')

# Calculate EBS volume savings
volumes = ec2.describe_volumes(
    Filters=[{'Name': 'status', 'Values': ['available']}]
)

total_size = sum(v['Size'] for v in volumes['Volumes'])
monthly_cost = total_size * 0.10  # illustrative input, not a verified gp3 rate

print(f"Unattached EBS Volumes: {len(volumes['Volumes'])}")
print(f"Total Size: {total_size} GB")
print(f"Monthly Savings: ${monthly_cost:.2f}")

# Calculate Elastic IP savings
addresses = ec2.describe_addresses()
unused = [a for a in addresses['Addresses'] if 'AssociationId' not in a]

eip_cost = len(unused) * 3.65  # $0.005/hour * 730 hours
print(f"\nUnused Elastic IPs: {len(unused)}")
print(f"Monthly Savings: ${eip_cost:.2f}")

print(f"\nTotal Monthly Savings: ${monthly_cost + eip_cost:.2f}")
print(f"Annual Savings: ${(monthly_cost + eip_cost) * 12:.2f}")

Automated Cleanup Lambda

import boto3
from datetime import datetime, timedelta

def lambda_handler(event, context):
    ec2 = boto3.client('ec2')
    
    # Discover candidates only; creation age is not detachment age.
    volumes = ec2.describe_volumes(
        Filters=[{'Name': 'status', 'Values': ['available']}]
    )
    
    cutoff = datetime.now() - timedelta(days=7)
    deleted = 0
    
    for vol in volumes['Volumes']:
        create_time = vol['CreateTime'].replace(tzinfo=None)
        if create_time < cutoff:
            try:
                print(f"Candidate only (not deleted): {vol['VolumeId']}")
            except Exception as e:
                print(f"Error deleting {vol['VolumeId']}: {e}")
    
    return {
        'statusCode': 200,
        'body': 'Dry run only; no volumes deleted'
    }

Cleanup Workflow

1. Discovery Phase (Read-only)

• Run all describe commands
• Generate cost impact report
• Review with team

1. Validation Phase

• Verify resources are truly unused
• Check for dependencies
• Notify resource owners

1. Execution Phase (Dry-run first)

• Run cleanup scripts with dry-run
• Review proposed changes
• Execute actual cleanup

1. Verification Phase

• Confirm deletions
• Monitor for issues
• Document savings

Safety Checklist

• [ ] Run in dry-run mode first
• [ ] Verify resources have no dependencies

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