optimizing-cloud-costs

What this skill does

# Optimizing Cloud Costs

## Overview

Analyze cloud spending across AWS, GCP, and Azure to identify waste, recommend rightsizing, and generate cost-saving configurations. Covers reserved instances, spot/preemptible workloads, storage tiering, idle resource cleanup, and budget alerting using cloud-native cost management APIs.

## Prerequisites

- Cloud provider CLI authenticated with billing/cost-explorer read access
- AWS: `ce:GetCostAndUsage`, `ec2:DescribeInstances`, `cloudwatch:GetMetricData` permissions
- GCP: Billing Account Viewer and Compute Viewer roles
- Azure: Cost Management Reader role
- Access to current infrastructure-as-code (Terraform, CloudFormation) for rightsizing changes
- At least 30 days of billing data for meaningful analysis

## Instructions

1. Pull current cost data using cloud cost APIs (`aws ce get-cost-and-usage`, `gcloud billing budgets list`)
2. Identify the top 10 cost drivers by service, region, and resource tag
3. Detect idle resources: instances with < 5% average CPU over 14 days, unattached EBS volumes, unused Elastic IPs, orphaned snapshots
4. Recommend rightsizing: compare instance utilization against available instance types and suggest downsizing
5. Evaluate reserved instance or savings plan coverage against on-demand spend; recommend commitments for steady-state workloads
6. Identify spot/preemptible candidates: stateless, fault-tolerant workloads (batch jobs, CI runners, dev environments)
7. Review storage costs: recommend S3 Intelligent-Tiering, lifecycle policies for infrequent access, or Glacier for archives
8. Generate Terraform/IaC changes to implement approved optimizations
9. Set up budget alerts with thresholds at 50%, 80%, and 100% of monthly budget
10. Create a cost optimization report summarizing findings, savings estimates, and implementation priority

## Output

- Cost analysis report with per-service breakdown and savings recommendations
- Terraform/CloudFormation changes for rightsizing and reserved instance purchases
- S3 lifecycle policy configurations for storage tiering
- Budget alert configurations (CloudWatch, GCP Budget, Azure Cost Alerts)
- Cleanup scripts for idle resources (with dry-run mode for safety)

## Error Handling

| Error | Cause | Solution |
|-------|-------|---------|
| `Access Denied on Cost Explorer API` | Missing `ce:*` IAM permissions | Attach the `AWSBillingReadOnlyAccess` managed policy to the IAM user/role |
| `No billing data available` | Account is too new or cost export not enabled | Enable Cost Explorer (takes 24h to populate) or set up CUR (Cost and Usage Report) |
| `Rightsizing recommendation breaks workload` | Instance too small for peak load | Base sizing on P95 utilization, not average; keep a 20% headroom buffer |
| `Spot instance terminated mid-job` | Spot capacity reclaimed by provider | Use spot fleet with diversified instance types and implement checkpointing |
| `Budget alert not firing` | SNS topic or notification channel misconfigured | Verify SNS subscription is confirmed and test with a low threshold |

## Examples

- "Analyze AWS costs for the last 3 months, identify the top waste areas, and generate a cleanup script for unattached EBS volumes and unused Elastic IPs."
- "Compare on-demand EC2 spend against Savings Plans pricing and recommend 1-year commitments for steady-state workloads."
- "Create S3 lifecycle policies to move objects older than 90 days to Glacier and delete after 365 days across all buckets tagged `env:production`."

## Resources

- AWS Cost Explorer: https://docs.aws.amazon.com/cost-management/latest/userguide/ce-what-is.html
- GCP Cost Management: https://cloud.google.com/billing/docs/how-to/budgets
- Azure Cost Management: https://learn.microsoft.com/en-us/azure/cost-management-billing/
- FinOps Foundation: https://www.finops.org/framework/