/ledger

Cost Visibility

Purpose: Design guide for tag strategy, cost allocation, dashboard specs, and showback/chargeback. Read when: Cost visibility, allocation, or report design is needed.

Tag Taxonomy Design

Hierarchical Tag Structure

TAG_HIERARCHY:
  business:
    cost-center: "CC-XXXX"       # Finance mapping
    business-unit: "engineering"  # Organization unit
    project: "project-alpha"     # Project tracking

  technical:
    team: "platform"             # Team ownership
    service: "api-gateway"       # Service name
    environment: "production"    # Deployment environment
    component: "backend"         # Service component

  operational:
    managed-by: "terraform"      # IaC tool
    owner: "alice@example.com"   # Primary contact
    created-date: "2026-01-15"   # Resource creation date

  cost_optimization:
    schedule: "business-hours"   # Auto start/stop
    commitment: "ri-eligible"    # RI/SP candidate
    criticality: "high"          # Business criticality

Tag Naming Conventions

Showback vs Chargeback

Shared Cost Allocation

Cost Dashboard Specification

Executive Dashboard

Team Dashboard

Engineering Dashboard

Unit Economics

Key Cost Metrics

Unit Cost Tracking Setup

-- Example BigQuery query for unit economics (GCP)
SELECT
  DATE_TRUNC(usage_start_time, MONTH) AS month,
  SUM(cost) AS total_cost,
  -- Join with application metrics
  app_metrics.total_requests,
  app_metrics.mau,
  SUM(cost) / app_metrics.total_requests AS cost_per_request,
  SUM(cost) / app_metrics.mau AS cost_per_user
FROM `billing_export.gcp_billing_export_v1_*`
JOIN `analytics.monthly_metrics` AS app_metrics
  ON DATE_TRUNC(usage_start_time, MONTH) = app_metrics.month
GROUP BY month, app_metrics.total_requests, app_metrics.mau
ORDER BY month DESC

Cost Report Template

## Monthly FinOps Report — {YYYY-MM}

### Executive Summary
- Total spend: $XX,XXX (budget: $XX,XXX, delta: +/- N%)
- MoM change: +/- N%
- Top cost driver: [service/team]
- Key action items: [1-3 items]

### Spend Breakdown
| Team | Spend | Budget | Delta | Trend |
|------|-------|--------|-------|-------|
| ... | ... | ... | ... | ↑/↓/→ |

### Optimization Wins
| Action | Monthly Savings | Implemented By |
|--------|----------------|----------------|
| ... | ... | ... |

### Open Opportunities
| Opportunity | Estimated Savings | Effort | Priority |
|-------------|-------------------|--------|----------|
| ... | ... | ... | ... |

### Commitment Status
- RI/SP coverage: N%
- Utilization: N%
- Expiring next quarter: [list]

### Next Month Actions
1. [Action 1]
2. [Action 2]
3. [Action 3]