[Initiative]: Substation Project Evolution Plan for CNCF Sandbox

### Name

Substation Project Evolution Plan for CNCF Sandbox

### Short description

Evolve the Substation project from AWS-specific implementations to cloud-agnostic event processing infrastructure patterns that align with CNCF goals, enabling integration with CNCF projects and meeting the requirements for CNCF Sandbox acceptance.

### Responsible group

TAG Operational Resilience

### Does the initiative belong to a subproject?

No

### Subproject name

_No response_

### Primary contact

Matt Young

### Additional contacts

_No response_

### Initiative description

# Substation Project Evolution Plan for CNCF Sandbox

## Description

Evolve the Substation project from AWS-specific implementations to cloud-agnostic event processing infrastructure patterns that align with CNCF goals, enabling integration with CNCF projects and meeting the requirements for CNCF Sandbox acceptance.

## Relevant TAGs/WGs

TAG Observability, TAG Security, TAG Contributor Strategy, potentially TAG App Delivery.

## Problem Statement

Substation provides production-proven event processing patterns currently implemented solely on AWS. To achieve broader adoption and contribute maximally to the cloud-native ecosystem, Substation needs to evolve into a cloud-agnostic framework while preserving its core value of providing scalable event processing plumbing for complex data flows.

## Scope

### In Scope

- Extract core event processing patterns from existing AWS implementation
- Document cloud-agnostic patterns and their operational characteristics
- Develop Crossplane XRDs (Composite Resource Definitions) to implement patterns in a cloud-native way
- Create local development environments for lower-friction contributions
- Integrate with key CNCF projects including OpenTelemetry and others
- Develop demonstrators to showcase Substation's utility in real-world CNCF applications
- Establish community development practices aligned with CNCF norms

### Out of Scope

- Implementation of all cloud providers initially (AWS reference implementation comes first)
- Building solution-specific applications beyond the demonstrators
- Taking on responsibilities of existing CNCF projects

## Goals

- Document cloud-agnostic event processing patterns extracted from production implementations
- Implement these patterns as Crossplane XRDs with a reference AWS implementation
- Create at least three demonstrators showing Substation's utility for the CNCF ecosystem
- Establish contribution guidelines and governance aligned with CNCF expectations
- Successfully apply for and enter the CNCF Sandbox program

## Non-Goals

- Replacing existing event processing systems
- Providing a complete application development framework
- Competing with messaging systems or workflow engines

## Implementation Plan

### Pattern Documentation & Abstraction

- Extract patterns from existing AWS implementation
- Create cloud-agnostic documentation and learning materials
- Define extension points and interfaces
- Document the patterns' operational, logistical, and performance characteristics

### Cloud-Native Reference Implementation

Brex's production implementation provides a proven test suite \-- the existing AWS Terraform configurations can serve as validation targets for the Crossplane resources. There's also a happy paved path to Crossplane from the existing AWS Terraform implementation, collaboration with the Crossplane project is essential to success; there are existing tools and accelerators. This all serves to de-risk the implementation of the XRD's, and will help the project to clearly communicate to adopters.

- Develop Crossplane XRDs for event infrastructure and necessary packaging
- Use existing AWS Terraform implementation as test suite for Crossplane XRD's
- Create a local development environment, deployable to a local cluster (kind or otherwise) to both lower the barriers to contribution as well as provide a useful CI/CD capability
- Enable viable paths to implementing support for additional cloud environments by embracing and utilizing the Crossplane ecosystem of Providers
- Integrate with OpenTelemetry to collect Observability signals, with configurations for the opentelemetry collector and default back ends
- Opportunity to partner within the Sandbox with other projects such as Perses, to provide dashboards and visibility into provisioned resources

### Core Value: Event Processing Plumbing

Substation provides foundational infrastructure patterns for scalable event processing including:

- Event routing topologies for complex data flows
- Transformation pipeline patterns for large-scale processing
- Fan-out/fan-in patterns for parallel processing
- Efficient streaming patterns for memory-constrained environments
- State management patterns for long-running processes

These patterns, while currently AWS-focused, are themselves cloud-agnostic. These can be made accessible with a familiar cloud native operating model via Crossplane Composite Resource Definitions ([XRDs](https://docs.crossplane.io/latest/concepts/composite-resource-definitions/)), which would codify the patterns in a cloud agnostic manner. These building blocks are useful for the CNCF's End User community and the foundation's own data processing needs.

### Integrations and Collaborations

- **CNCF Projects**: Crossplane, OpenTelemetry, Perses, Argo, TiKV

## Resource Requirements

- CNCF resources for project management, guidance, licensing, and infrastructure
- TAG Contributor Strategy engagement
- TAG Security engagement
- Substation Project team engagement
- Cross-project collaboration and outreach (TiKV, Crossplane, Argo, etc...)
- Academic partnership support

## Timeline

Estimate: 6 months for initial implementation plan execution Current Date: May 11, 2025

## 6-Month Implementation Plan

1. **Months 1-2**: Document patterns, set up local development environment
2. **Months 2-4**: Develop Crossplane XRDs, implement AWS reference
3. **Months 3-5**: Build demonstrators, integrate with CNCF projects
4. **Months 5-6**: Community development, final Sandbox application preparation

## Additional References

1. [Substation Sandbox Application](https://github.com/cncf/sandbox/issues/117) \- Original CNCF Sandbox application
2. [Crossplane Documentation](https://docs.crossplane.io/) \- Core technology for cloud-agnostic implementation
3. [OpenTelemetry Integration Guide](https://opentelemetry.io/docs/instrumentation/go/) \- Observability integration

### Deliverable(s) or exit criteria

- Documented cloud-agnostic event processing patterns
- Implementation of patterns as Crossplane XRDs
- At least three demonstrator applications showing real-world value
- Successful integration with key CNCF projects
- Community engagement metrics (contributors, adopters)
- Acceptance into CNCF Sandbox program

Start by reviewing the existing AWS Terraform configurations, then read the linked Crossplane Documentation and OpenTelemetry Integration Guide to understand the proposed implementation direction. Done requires coordinating a six-month, cross-project effort producing documented cloud-agnostic patterns, Crossplane XRDs, three demonstrators, integrations, and a Sandbox application.

Written by the indexing model from the issue text.