Learning track

This project is built to learn how an enterprise event platform is designed and operated, and to show why each decision is made so the reasoning can be followed and reused (ADR 0023).

Folder	Contents
concepts/	One note per concept: what it is, why it exists, what can go wrong, options, how to decide
retros/	One retrospective per phase: system-level decisions and lessons

Learning path

Phase	Concepts	Notes
0 · Foundation	Decision records, shift-left repository hygiene, supply-chain pinning, regulatory mapping, documentation types	Retro
1 · Cluster	Infrastructure-as-code state (backend, locking, encryption), the bootstrap problem, secret zero, layered provisioning, GitOps reconciliation	OpenTofu state · Secret zero · GitOps reconciliation and ownership · Cattle, not pets · Retro
2 · Platform	Policy as code, metrics/logs/traces, secrets management, log retention, TLS automation	upcoming
3 · Kafka	Replication and ISR, KRaft quorum, TLS/SCRAM and ACLs, schema evolution	upcoming
4 · Apps	Exactly-once processing, deterministic state machines, order books, idempotency, market surveillance	upcoming
5 · Tests	Testing a platform at every layer, chaos engineering	upcoming
6 · Billion run	Performance methodology, end-to-end reconciliation	upcoming
7 · Resilience	RPO/RTO, failure domains, backup versus replication	upcoming
8 · Lifecycle	Upgrade ordering, irreversible changes, maintenance windows	upcoming