AWS Cost Optimizer

When to Use This Skill

Core Capabilities

• Parse AWS Cost Explorer data for trends and anomalies
• Break down costs by service, region, and resource tags
• Identify month-over-month spending increases

• Detect idle EC2 instances (low CPU utilization)
• Find unattached EBS volumes and old snapshots
• Identify unused Elastic IPs
• Locate underutilized RDS instances
• Find old S3 objects eligible for lifecycle policies

• Suggest Reserved Instance/Savings Plans opportunities
• Recommend instance rightsizing based on CloudWatch metrics
• Identify resources in expensive regions
• Calculate potential savings with specific actions

AWS CLI Commands

Get Cost and Usage

# Last 30 days cost by service
aws ce get-cost-and-usage \
  --time-period Start=$(date -d '30 days ago' +%Y-%m-%d),End=$(date +%Y-%m-%d) \
  --granularity MONTHLY \
  --metrics BlendedCost \
  --group-by Type=DIMENSION,Key=SERVICE

# Daily costs for current month
aws ce get-cost-and-usage \
  --time-period Start=$(date +%Y-%m-01),End=$(date +%Y-%m-%d) \
  --granularity DAILY \
  --metrics UnblendedCost

Find Unused Resources

# Unattached EBS volumes
aws ec2 describe-volumes \
  --filters Name=status,Values=available \
  --query 'Volumes[*].[VolumeId,Size,VolumeType,CreateTime]' \
  --output table

# Unused Elastic IPs
aws ec2 describe-addresses \
  --query 'Addresses[?AssociationId==null].[PublicIp,AllocationId]' \
  --output table

# Idle EC2 instances (requires CloudWatch)
aws cloudwatch get-metric-statistics \
  --namespace AWS/EC2 \
  --metric-name CPUUtilization \
  --dimensions Name=InstanceId,Value=i-xxxxx \
  --start-time $(date -u -d '7 days ago' +%Y-%m-%dT%H:%M:%S) \
  --end-time $(date -u +%Y-%m-%dT%H:%M:%S) \
  --period 86400 \
  --statistics Average

# Old EBS snapshots (>90 days)
aws ec2 describe-snapshots \
  --owner-ids self \
  --query 'Snapshots[?StartTime<=`'$(date -d '90 days ago' --iso-8601)'`].[SnapshotId,StartTime,VolumeSize]' \
  --output table

Rightsizing Analysis

# List EC2 instances with their types
aws ec2 describe-instances \
  --query 'Reservations[*].Instances[*].[InstanceId,InstanceType,State.Name,Tags[?Key==`Name`].Value|[0]]' \
  --output table

# Get RDS instance utilization
aws cloudwatch get-metric-statistics \
  --namespace AWS/RDS \
  --metric-name CPUUtilization \
  --dimensions Name=DBInstanceIdentifier,Value=mydb \
  --start-time $(date -u -d '30 days ago' +%Y-%m-%dT%H:%M:%S) \
  --end-time $(date -u +%Y-%m-%dT%H:%M:%S) \
  --period 86400 \
  --statistics Average,Maximum

Optimization Workflow

1. Baseline Assessment
   • Pull 3-6 months of cost data
   • Identify top 5 spending services
   • Calculate growth rate
2. Quick Wins
   • Delete unattached EBS volumes
   • Release unused Elastic IPs
   • Stop/terminate idle EC2 instances
   • Delete old snapshots
3. Strategic Optimization
   • Analyze Reserved Instance coverage
   • Review instance types vs. workload
   • Implement S3 lifecycle policies
   • Consider Spot instances for non-critical workloads
4. Ongoing Monitoring
   • Set up AWS Budgets with alerts
   • Enable Cost Anomaly Detection
   • Tag resources for cost allocation
   • Monthly cost review meetings

Cost Optimization Checklist

• Enable AWS Cost Explorer
• Set up cost allocation tags
• Create AWS Budget with alerts
• Review and delete unused resources
• Analyze Reserved Instance opportunities
• Implement S3 Intelligent-Tiering
• Review data transfer costs
• Optimize Lambda memory allocation
• Use CloudWatch Logs retention policies
• Consider multi-region cost differences

Example Prompts

• "Show me AWS costs for the last 3 months broken down by service"
• "What are my top 10 most expensive resources?"
• "Compare this month's spending to last month"

• "Find all unattached EBS volumes and calculate savings"
• "Identify EC2 instances with <5% CPU utilization"
• "Suggest Reserved Instance purchases based on usage"
• "Calculate savings from deleting snapshots older than 90 days"

• "Create a script to delete unattached volumes"
• "Set up a budget alert for $1000/month"
• "Generate a cost optimization report for leadership"

Best Practices

• Always test in non-production first
• Verify resources are truly unused before deletion
• Document all cost optimization actions
• Calculate ROI for optimization efforts
• Automate recurring optimization tasks
• Use AWS Trusted Advisor recommendations
• Enable AWS Cost Anomaly Detection

Integration with Kiro CLI

# Use Kiro to analyze costs
kiro-cli chat "Use aws-cost-optimizer to analyze my spending"

# Generate optimization report
kiro-cli chat "Create a cost optimization plan using aws-cost-optimizer"

Safety Notes

• Risk Level: Low - Read-only analysis is safe
• Deletion Actions: Medium Risk - Always verify before deleting resources
• Production Changes: High Risk - Test rightsizing in dev/staging first
• Maintain backups before any deletion
• Use

  --dry-run

  flag when available

Additional Resources

• AWS Cost Optimization Best Practices
• AWS Well-Architected Framework - Cost Optimization
• AWS Cost Explorer API