# Cost Service

Per-vehicle cost estimation service for capacity planning and cloud vs on-prem comparison.

## Overview

This service estimates the cost of running cloud services per VIN by:
1. Querying vehicle activity from ClickHouse (message counts)
2. Estimating resource usage based on activity level
3. Applying cost rates for cloud vs on-prem hosting
4. Storing aggregated cost data for reporting

## Cost Estimation Methodology

### Cost Model

The cost model separates fixed platform costs from variable per-VIN costs:

```
Total Cost = Platform Base Cost + (Per-VIN Cost × Number of VINs) + Managed Services
```

Whether you have 100 vehicles or 100,000, you still need Kafka, databases, and gateway services running. That's your platform base cost. Then each additional vehicle adds a small marginal cost on top.

### Platform Base Resources (Fixed)

What it takes to run the cloud services platform (from migration plan v1.1):

| Component | CPU (cores) | Memory (GB) | Notes |
|-----------|-------------|-------------|-------|
| VM 1-4: Core Services | 16 | 64 | Kafka, OTA, Valet, Auth/APIs |
| VM 5: Analytics Primary | 32 | 256 | ClickHouse, Ditto, Beacon, Jetfire |
| VM 6: Analytics Secondary | 32 | 256 | Optimus, Cargo, Vehicle Analytics |
| **Total Platform Base** | **80** | **544** | Based on migration plan |

### Per-VIN Resources (Marginal)

Incremental resources needed for each additional connected vehicle:

| Activity Level | Messages/15min | CPU (millicores) | Memory (MB) |
|---------------|----------------|------------------|-------------|
| Low           | < 100          | 3                | 10          |
| Medium        | 100-1000       | 5                | 15          |
| High          | > 1000         | 6                | 20          |

**Derivation (from cec-prd-cluster-1 metrics, 2026-02-05):**
- Event Hubs: ~90M messages/hour, ~230GB/hour incoming
- Active VINs: ~3,760
- AKS cluster usage: ~43 cores / ~219GB RAM
- Estimated platform base: ~34 cores / ~175GB (ClickHouse, Kafka consumers, services)
- Per-VIN marginal: (43-34)/3760 ≈ 2.4mc, (219-175)/3760 ≈ 12MB
- Rounded to 3mc / 10MB for conservative estimate

### Cost Rates

| Resource | Cloud (Azure) | On-Prem/Bare Metal |
|----------|---------------|-------------------|
| CPU/core-hour | $0.35 | $0.015 |
| Memory/GB-hour | $0.10 | $0.004 |
| Managed Services/15min | $17.00 | $1.50 |

#### Why On-Prem is ~90-95% Cheaper
- **Platform base**: Same workload, but cloud charges ~20x more for managed services
- **Per-VIN compute**: Cloud VMs cost ~20x more than amortized bare metal
- **Managed services**: Event Hubs, CosmosDB, Azure DB for PostgreSQL have significant markup vs self-hosted

### Savings Calculation

```
Platform Base Cost = (80 cores × rate + 544 GB × rate) × hours
Per-VIN Cost = (0.003 cores × rate + 0.01 GB × rate) × hours × activity_multiplier
Total Cost = Platform Base + (Per-VIN × VIN count) + Managed Services

Cloud Cost = Total with cloud rates
On-Prem Cost = Total with on-prem rates  
Savings = Cloud Cost - On-Prem Cost
Savings % = (Savings / Cloud Cost) × 100
```

Expected savings: **~90-95%** with on-prem/bare metal hosting.

### Projected Annual Costs

Based on ~$1M/year Azure spend (migration plan v1.1):

| Metric | Cloud | On-Prem |
|--------|-------|---------|
| Monthly Cost | ~$83,000 | ~$7,000 |
| Annual Cost | ~$1,000,000 | ~$84,000 |
| Annual Savings | ~$916,000 (92%) | - |

## API Endpoints

### GET /cost/vin/{vin}
Cost summary for a specific VIN.

### GET /cost/fleet
Fleet-wide cost summary with top cost VINs.

### GET /cost/summary?period=day|week|month
High-level cost summary for a time period.

### GET /cost/comparison
Cloud vs on-prem cost comparison with projected annual savings.

### GET /cost/report
Plain text report for terminal viewing.

## Accessing the Report

The service is deployed internally on cec-prd-cluster-1 (no public ingress). To view the report:

```bash
# Quick one-liner
kubectl --context cec-prd-cluster-1 run curl-test --image=curlimages/curl --rm -it --restart=Never -- curl -s http://cost.default.svc.cluster.local:8077/cost/report

# Or port-forward and curl locally
kubectl --context cec-prd-cluster-1 port-forward svc/cost 8077:8077 &
curl http://localhost:8077/cost/report
```

## Example Report Output

```
╔══════════════════════════════════════════════════════════════════╗
║                    COST SERVICE REPORT                           ║
╠══════════════════════════════════════════════════════════════════╣
║  Period: 2026-01-05 to 2026-02-05
╠══════════════════════════════════════════════════════════════════╣
║  FLEET OVERVIEW                                                  ║
║  ─────────────────────────────────────────────────────────────── ║
║  Active Vehicles:     2463                                         
║  Cloud Cost:          $695.52                                      
║  On-Prem Cost:        $62.55                                      
║  Savings:             $632.97 (91.0%)                             
╠══════════════════════════════════════════════════════════════════╣
║  RESOURCE USAGE MODEL                                            ║
║  ─────────────────────────────────────────────────────────────── ║
║  Platform Base:       80 cores / 544 GB RAM (fixed)              
║  Per-VIN Marginal:    3 millicores / 10 MB RAM                   
║  Total Fleet:         87.4 cores / 568.6 GB RAM                 
╠══════════════════════════════════════════════════════════════════╣
║  COST FORMULA                                                    ║
║  ─────────────────────────────────────────────────────────────── ║
║  (Platform Base) + (Per-VIN × 2463 VINs) + Managed Services       
╠══════════════════════════════════════════════════════════════════╣
║  COST RATES                                                      ║
║  ─────────────────────────────────────────────────────────────── ║
║  Cloud:   CPU $0.35/core-hr   Memory $0.100/GB-hr                 
║  On-Prem: CPU $0.01/core-hr   Memory $0.004/GB-hr                 
║  Base Infra: Cloud $17.00/15min   On-Prem $1.50/15min             
╠══════════════════════════════════════════════════════════════════╣
║  ANNUAL PROJECTION (based on current usage)                      ║
║  ─────────────────────────────────────────────────────────────── ║
║  Cloud Annual:        $8346.25                                      
║  On-Prem Annual:      $750.61                                      
║  Annual Savings:      $7595.65                                      
╚══════════════════════════════════════════════════════════════════╝

TOP COST VEHICLES:
VIN                    CPU (mc)   RAM (MB)      Cloud $    On-Prem $  Savings %
───────────────────    ────────   ────────   ──────────   ──────────   ────────
VCF1UBU21RG013084            94        149         1.20         0.12      90.4%
VCF1EBU21RG012448            94        149         1.20         0.12      90.4%
VCF1EBU22PG011385            94        149         1.20         0.12      90.4%
VCF1EBU24PG011467            94        149         1.20         0.12      90.4%
VCF1EBU29PG007298            94        149         1.20         0.12      90.4%
...
```

*Note: Report generated 2026-02-05. Costs accumulate over time as the collector runs every 15 minutes.*

## Configuration

| Env Var | Description | Default |
|---------|-------------|---------|
| CLICKHOUSE_HOST | Local CH for storing cost data | localhost |
| REMOTE_CLICKHOUSE_HOST | Dev cluster CH for VIN activity | - |
| COLLECTOR_INTERVAL_MINUTES | How often to collect metrics | 15 |

## Limitations

- Resource estimates are approximations, not actual measurements
- Cost rates are simplified and don't reflect all real-world factors
- On-prem costs exclude significant operational overhead
- Designed for business case illustration, not precise billing