Building New vs. Transforming Existing Systems

Every organization faces a fundamental choice: build new cloud-native systems from scratch (greenfield) or transform existing systems (brownfield). This choice shapes everything from architecture decisions to team structure. Understanding both approaches is crucial for Europe's cloud independence journey.

The Greenfield Dream

Starting fresh with a greenfield project is every engineer's dream. No legacy code, no technical debt, no compromises. You can choose the best technologies and build exactly what you need. For a new IoT platform serving agriculture, for example, you might choose:

• Kubernetes for orchestration, providing portability and scalability
• Apache Kafka for event streaming, replacing proprietary message queues
• TimescaleDB for time-series data, avoiding vendor-specific databases
• Prometheus and Grafana for monitoring, using open-source standards
• K3s on edge devices for distributed computing at sensor locations

This architecture would be cloud-agnostic, running equally well on OVHcloud, Scaleway, or your own infrastructure.

The Brownfield Reality

Consider a real-world IoT platform with 400 customers, processing billions of events monthly. It runs on AWS using EC2, DynamoDB, SQS, and various other proprietary services. The team knows these services intimately. The platform is reliable and profitable. But it's also completely locked into AWS.

Transforming such a system requires careful planning:

Phase 1: Containerize and Standardize Start with stateless services. Move Python and Scala workers from EC2 to containers. Deploy them on EKS (Amazon's Kubernetes) initially.

Phase 2: Replace Commoditized Services Tackle standardized services next. Move from Amazon Elasticsearch to the Elasticsearch Operator on Kubernetes. Replace CloudWatch with Prometheus and Grafana.

Phase 3: Strategic Service Migration The hard part: replacing services like DynamoDB and SQS. Move from SQS to Apache Kafka—not just a queue replacement but an opportunity for new event-driven features.

Phase 4: Infrastructure Portability Once services are containerized and using open standards, you can move workloads. Start with development environments on European clouds.

Patterns for Success

Whether greenfield or brownfield, successful transformations share patterns:

Start Small, Think Big: Begin with pilot projects that prove concepts. Design for the end state but implement incrementally.

Invest in Knowledge: Cloud-native transformation is as much about people as technology. Train teams, hire expertise, engage partners.

Maintain Business Continuity: Never risk the business for technical purity. Keep systems running while transforming them.

The Hybrid Future

The greenfield/brownfield distinction is becoming less relevant. Modern architectures support gradual transformation. You can run cloud-native workloads alongside legacy systems, moving functionality piece by piece.

For Europe, this means we don't need to abandon existing investments to achieve cloud independence. We can transform gradually, maintaining business continuity while building sovereignty.

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