RFC00002 Kubernetes Deployment with Helm Charts for BharatMLStack

rfc/00002/k8s-helm-rfc.md

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+# RFC: Kubernetes Deployment with Helm Charts for BharatMLStack
+
+## Metadata
+- **Title**: Kubernetes Deployment Strategy using Helm Charts for BharatMLStack
+- **Author**: Raju Gupta
+- **Status**: Draft
+- **Created**: 2025-07-26
+- **Last Updated**: 2025-07-26
+- **Repository**: [Meesho/BharatMLStack](https://github.com/Meesho/BharatMLStack)
+- **Target Release:** v1.0.0
+- **Discussion Channel:** #infra-dev
+
+## 🎯 Motivation
+
+BharatMLStack powers core ML infrastructure — including **Online Feature Store**, **Horizon (control plane backend)**, and **Trufflebox UI** — to support high-throughput inference, training, and real-time feature retrieval.
+
+The current deployment methods are manual and component-specific, making it hard to:
+- Standardize deployment patterns across components.
+- Onboard new contributors or operators quickly.
+- Maintain consistent security and observability standards.
+
+A **Helm-based deployment approach** is needed to:
+- **Simplify deployment** for ML engineers and data scientists.
+- **Enable consistent configuration as code** across all environments.
+- **Support production-grade scaling** (VPA,HPA, PDB, Gateway routing).
+- **Adopt cloud-native best practices** from the start.
+
+## ✅ Goals
+
+- Provide **modular Helm charts** for core components:  
+  **Online Feature Store**, **Horizon** and **Trufflebox UI**.
+- Support **Ingress** (default) and **Gateway API** (production-ready routing).
+- Embed **security & observability best practices** (RBAC, NetworkPolicy, ServiceMonitor).
+- Enable environment-specific overrides (`values-dev.yaml`, `values-prod.yaml`).
+- Provide a **contributor-friendly structure** (clear templates, tests, CI-ready).
+
+## 🚫 Non-Goals
+
+- Provisioning Kubernetes clusters or cloud infrastructure.
+- Managing third-party services (Redis, Scylla, Postgres) beyond optional values.
+- Providing GitOps or CI/CD pipelines (only chart testing and linting).
+- Combining components into a single “umbrella chart” (initial phase is modular).
+
+## 🧱 Proposed Directory Structure
+
+The Helm charts are **modularized per core component** for independent development, deployment, and scaling.  
+Each component explicitly supports **Ingress** and **Gateway API** (Gateway + HTTPRoute).
+
+```
+bharatmlstack/helm/
+├── online-feature-store/                  # Core real-time feature store
+│   ├── Chart.yaml
+│   ├── values.yaml
+│   ├── values-dev.yaml
+│   ├── values-prod.yaml
+│   └── templates/
+│       ├── deployment.yaml
+│       ├── service.yaml
+│       ├── ingress.yaml
+│       ├── gateway.yaml
+│       ├── httproute.yaml
+│       ├── configmap.yaml
+│       ├── secret.yaml
+│       ├── hpa.yaml
+│       ├── vpa.yaml
+│       ├── networkpolicy.yaml
+│       ├── servicemonitor.yaml
+│       ├── pdb.yaml
+│       └── tests/
+│           ├── latency-test.yaml
+│           └── api-test.yaml
+
+├── horizon/                               # Control plane backend
+│   ├── Chart.yaml
+│   ├── values.yaml
+│   ├── values-dev.yaml
+│   ├── values-prod.yaml
+│   └── templates/
+│       ├── deployment.yaml
+│       ├── service.yaml
+│       ├── ingress.yaml
+│       ├── gateway.yaml
+│       ├── httproute.yaml
+│       ├── configmap.yaml
+│       ├── secret.yaml
+│       ├── hpa.yaml
+│       ├── vpa.yaml
+│       ├── networkpolicy.yaml
+│       ├── servicemonitor.yaml
+│       ├── pdb.yaml
+│       └── tests/
+│           └── api-test.yaml
+
+├── trufflebox-ui/                         # Management console
+│   ├── Chart.yaml
+│   ├── values.yaml
+│   ├── values-dev.yaml
+│   ├── values-prod.yaml
+│   └── templates/
+│       ├── deployment.yaml
+│       ├── service.yaml
+│       ├── ingress.yaml
+│       ├── gateway.yaml
+│       ├── httproute.yaml
+│       ├── configmap.yaml
+│       ├── secret.yaml
+│       ├── hpa.yaml
+│       ├── vpa.yaml
+│       ├── networkpolicy.yaml
+│       ├── servicemonitor.yaml
+│       ├── pdb.yaml
+│       └── tests/
+│           └── ui-availability.yaml
+```
+
+## 🌐 Ingress and Gateway API Support
+
+### Why Both?
+- **Ingress (NGINX/Traefik)** → Default, widely supported, ideal for dev/local.
+- **Gateway API** → Kubernetes future standard, ideal for production-grade routing, traffic-splitting, and multi-tenant use cases.
+
+### Example Values
+```yaml
+ingress:
+  enabled: true
+  className: "nginx"
+  host: bharatmlstack.local
+
+gateway:
+  enabled: false
+  className: "istio"
+  host: bharatmlstack.prod.com
+  tls:
+    enabled: true
+    secretName: bharatmlstack-tls
+```
+
+## 📝 Contribution Workflow
+
+- Fork the repository and work under `bharatmlstack/helm/<component>/`.
+- Run `helm lint` and `helm template` before raising PRs.
+- Update/add Helm test hooks in `templates/tests/`.
+- Ensure changes work with KinD or Minikube (CI will validate).
+- Update `values-*.yaml` for new configs.