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GreenKube

Flexible Storage

GreenKube is storage-agnostic by design. The application core never depends on a specific storage implementation, letting you choose the backend that best fits your use case.

Supported Backends

Section titled “Supported Backends”
Section titled “PostgreSQL (Recommended for Production)”
  • Full SQL support with time-series optimized queries
  • Included in the Helm chart as a StatefulSet
  • Persistent storage with configurable PVC
  • Supports connection pooling and replicas
values.yaml
greenkube:
  dbType: "postgresql"
postgresql:
  enabled: true
  storage: "10Gi"

SQLite (Development & Standalone)

Section titled “SQLite (Development & Standalone)”
  • Zero infrastructure — single file database
  • Perfect for local development and testing
  • Great for single-node standalone deployments
  • No additional services required
greenkube:
  dbType: "sqlite"
  sqlitePath: "/data/greenkube.db"

Elasticsearch (Scale & Analytics)

Section titled “Elasticsearch (Scale & Analytics)”
  • Optimized for large-scale metric storage
  • Advanced time-series aggregation queries
  • Integrates with Kibana for additional visualization
  • Ideal for organizations already running an ELK stack
greenkube:
  dbType: "elasticsearch"
  elasticsearchUrl: "http://elasticsearch:9200"

Repository Pattern

Section titled “Repository Pattern”

The storage agnosticism is achieved through the Repository Pattern:

┌──────────────────┐
│   Business Logic  │  ← Calls repository.save_metric()
│   (Core)          │     Never knows about SQL/NoSQL
└────────┬─────────┘
         │ interface
┌────────┴─────────┐
│   Repository      │  ← Abstract interface
│   Interface       │
└────────┬─────────┘
    ┌────┼────┐
    ▼    ▼    ▼
  PG  SQLite  ES     ← Concrete implementations

This means:

  • Switching backends requires only a configuration change
  • The business logic is fully tested without any real database
  • New backends can be added without touching the core

Factory Pattern

Section titled “Factory Pattern”

Backend instantiation is handled by core/factory.py:

# Simplified example
def create_repository(config: Config) -> MetricRepository:
    if config.db_type == "postgresql":
        return PostgreSQLRepository(config.db_url)
    elif config.db_type == "sqlite":
        return SQLiteRepository(config.sqlite_path)
    elif config.db_type == "elasticsearch":
        return ElasticsearchRepository(config.es_url)

Migration Between Backends

Section titled “Migration Between Backends”

GreenKube supports data export/import to facilitate migration:

Terminal window
# Export from current backend
greenkube export --format json --output metrics.json


# Import into new backend
greenkube import --input metrics.json
Section titled “Related”