Phase 4: Hetzner Infrastructure Implementation

[josecelano]

Objective

Add Hetzner Cloud provider support and validate complete deployment.

This issue implements Phase 4 of the parent issue #3 (Migrate Torrust Tracker Demo from Digital Ocean to Hetzner).

Scope

Implement a multi-provider architecture that properly separates environments from infrastructure providers, ensuring the system can scale to support unlimited providers without code changes.

Design Approach

• Clear Separation: Environment (development/staging/production) vs Provider (libvirt/hetzner/aws/etc.)
• Pluggable Provider System: Each provider self-contained with standard interface
• Scalable Architecture: Adding new providers requires zero changes to existing code
• Zero Breaking Changes: Backward compatibility maintained with default values

Tasks

Core Architecture

• Rename environment files (local → development) to avoid confusion
• Create provider interface system (infrastructure/scripts/providers/provider-interface.sh)
• Implement pluggable provider modules in infrastructure/terraform/providers/
• Update Makefile to require both ENVIRONMENT and PROVIDER parameters

Hetzner Provider Implementation

• Create Hetzner Cloud OpenTofu provider configuration
• Implement Hetzner-specific Terraform configurations
• Create Hetzner provider script with standard interface functions
• Add Hetzner cloud-init adaptations
• Create provider-specific environment templates

Enhanced Commands

• Add make infra-providers - List available providers
• Add make infra-environments - List available environments
• Add make provider-info PROVIDER=hetzner - Get provider details
• Update all infrastructure commands to use ENVIRONMENT + PROVIDER pattern

Validation

• Test complete deployment pipeline on Hetzner
• Verify all services start correctly
• Test tracker functionality (announce, scrape)
• Confirm firewall rules work correctly
• Performance and connectivity testing

Usage Examples

# Development environment on local infrastructure
make infra-apply ENVIRONMENT=development PROVIDER=libvirt

# Staging environment on DigitalOcean (future)
make infra-apply ENVIRONMENT=staging PROVIDER=digitalocean

# Production environment on Hetzner
make infra-apply ENVIRONMENT=production PROVIDER=hetzner

Implementation Plan

Detailed implementation plan available in: docs/plans/multi-provider-architecture-plan.md

Definition of Done

• Multi-provider architecture implemented with pluggable system
• Hetzner provider working and tested
• All existing commands work with backward compatibility
• No hardcoded provider logic in core scripts
• Complete deployment validated on Hetzner
• Documentation updated

Related Issues

• Parent: Migrate Torrust Tracker Demo from Digital Ocean to Hetzner #3 - Migrate Torrust Tracker Demo from Digital Ocean to Hetzner
• Depends on: Use MYSQL instead of SQLite by default #12 (MySQL), Phase 2: 12-Factor App Refactoring #14 (12-Factor), Phase 3: Complete Application Installation Automation #21 (Automation) - all completed

Provider Firewall Consideration

• VM firewall via cloud-init: ✅ Required
• Provider firewall: 🤔 Optional additional security layer

Deliverable

Working Hetzner deployment with IP access and clean multi-provider architecture that scales to unlimited providers.