openova/docs/ARCHITECTURE.md

Catalyst Architecture

Status: Authoritative target architecture. Updated: 2026-04-29. Implementation: Most of what this document describes is design-stage — see IMPLEMENTATION-STATUS.md for what exists in code today vs what is design. The DNS plane (bp-powerdns + pool-domain-manager + registrar adapters) is deployed today in openova-system on Catalyst-Zero.

This document describes the architecture of Catalyst — the OpenOva platform. For terminology, defer to GLOSSARY.md. For naming, defer to NAMING-CONVENTION.md. For current code state, defer to IMPLEMENTATION-STATUS.md.

---

1. The platform in one paragraph

Catalyst is a self-sufficient Kubernetes-native control plane published as signed OCI Blueprints. A single deployed Catalyst is called a Sovereign. Inside a Sovereign, Organizations are the multi-tenancy unit. An Organization has Environments ({org}-prod, {org}-dev, etc.) where users install Applications from Blueprints. Each Application is its own Gitea repo (one App = one repo, uniformly across SME and corporate scale); branches develop/staging/main map to dev/stg/prod environments. One or more vclusters per Environment run lightweight Flux watching the appropriate branch across the Org's Application repos. Every state change flows through NATS JetStream, projects into per-Environment KV via the projector service, and reaches the console via SSE — so every UI surface sees the same picture, derived from Git (write side) and Kubernetes (runtime side) without fragmenting. Crossplane handles all non-Kubernetes resources. OpenBao + ESO + SPIRE handles secrets and workload identity. Keycloak handles user identity. Same code runs in every Sovereign — whether it's run by us, by Omantel, or by Bank Dhofar.

---

2. Two scales, one architecture

The model serves two distinct customer shapes through the same code:

        ┌──────────────────────────────────────────────────────────────┐
        │ SME-style Sovereign (e.g. omantel)                           │
        │                                                               │
        │ Many small Organizations, mostly single-Environment           │
        │ Each Org gets its own minimal Keycloak (no HA)                │
        │ Self-service marketplace, next-next-next install              │
        │ Sovereign-admins are the SaaS provider's cloud team           │
        └──────────────────────────────────────────────────────────────┘

        ┌──────────────────────────────────────────────────────────────┐
        │ Corporate-style Sovereign (e.g. bankdhofar)                  │
        │                                                               │
        │ Few internal Organizations (core-banking, digital-channels…)  │
        │ One Sovereign-wide Keycloak (federates to corporate Azure AD) │
        │ Rich governance: EnvironmentPolicy, soak gates, approvers     │
        │ Sovereign-admins are the bank's platform team                 │
        │ Multi-region default; multi-Environment per Org default       │
        └──────────────────────────────────────────────────────────────┘

The only runtime configuration difference is set at provisioning time:

keycloakTopology: per-organization      # SME default
# or
keycloakTopology: shared-sovereign      # Corporate default

Everything else is identical in code.

---

3. Topology

┌─────────────────────────────────────────────────────────────────────────┐
│ Sovereign: omantel                                                       │
│                                                                           │
│  Management host cluster: hz-nbg-mgt-prod                                 │
│  ┌────────────────────────────────────────────────────────────────────┐ │
│  │ Catalyst control plane (in catalyst-* namespaces)                   │ │
│  │   console   marketplace   admin   catalog-svc   projector           │ │
│  │   provisioning   environment-controller   blueprint-controller      │ │
│  │   billing                                                            │ │
│  │   gitea   nats-jetstream   openbao   keycloak   spire-server        │ │
│  │   observability (Grafana stack)                                      │ │
│  └────────────────────────────────────────────────────────────────────┘ │
│  Plus per-host-cluster infrastructure (Cilium, Flux, Crossplane,         │
│  cert-manager, External-Secrets, Kyverno, Harbor, Reloader, Trivy,       │
│  Falco, Sigstore, Syft+Grype, VPA, KEDA, External-DNS, PowerDNS, Coraza, │
│  SeaweedFS, Velero, failover-controller) — see PLATFORM-TECH-STACK §3.   │
│                                                                           │
│  Workload host clusters: hz-fsn-rtz-prod, hz-hel-rtz-prod                 │
│  ┌──────────────────────────────────────────────────────────────────┐   │
│  │ Per-Org vcluster (named {org}):                                  │   │
│  │   muscatpharmacy   acme-shop   blue-pharmacy   …                 │   │
│  │   each runs its own lightweight Flux pointed at the Environment  │   │
│  │   Gitea repo                                                     │   │
│  └──────────────────────────────────────────────────────────────────┘   │
│                                                                           │
│  DMZ host clusters: hz-fsn-dmz-prod, hz-hel-dmz-prod                      │
│   Cilium Gateway, WAF (Coraza), PowerDNS authoritative + lua-records,    │
│   dnsdist rate-limit, WireGuard endpoints                                 │
└─────────────────────────────────────────────────────────────────────────┘
                              ↕
                  Gitea (in management cluster) — 5 conventional Gitea Orgs
                  ──────────────────────────────────────────────────────────
                  catalog/                    ← public Blueprint mirror (read-only)
                  catalog-sovereign/          ← Sovereign-owner-curated private Blueprints (optional)
                  acme-pharmacy/              ← one Gitea Org per Catalyst Organization
                    ├── shared-blueprints     ← Org-private Blueprint authoring
                    ├── store-frontend        ← one Gitea Repo per Application
                    ├── pharmacy-mail
                    ├── consult-room
                    └── appointments
                                              (branches develop/staging/main map
                                               to dev/stg/prod environments)
                  kestrel-rx/                 ← another Catalyst Organization
                    ├── shared-blueprints
                    └── ...
                  system/                     ← sovereign-admin scope
                    ├── catalyst-config       (CRs: Sovereign, Organization,
                    │                          Environment, EnvironmentPolicy)
                    ├── policy-bundle         (Kyverno, Falco, RE Scorecard)
                    └── runbooks              (auto-remediation)
                  ...

Sovereign self-sufficiency: once a Sovereign is provisioned, it has its own Gitea, its own JetStream, its own OpenBao, its own Keycloak, its own Crossplane. It does not depend on any other Sovereign at runtime. OpenOva's openova Sovereign is in the picture only as the publisher of public Blueprints — and even those are mirrored locally, so the Sovereign keeps working if openova.io disappears.

---

4. Write side: Git → Flux → Kubernetes (+ Crossplane)

                       Console UI                       REST/GraphQL API
                            │                                    │
                            │  (Git push from any of these       │
                            │   bypasses provisioning and goes   │
                            │   straight to the App's repo;      │
                            │   webhook + projector still fire)  │
                            ▼                                    ▼
              ┌──────────────────────────────────────────────────────────┐
              │  provisioning service                                    │
              │   - validates configSchema against Blueprint              │
              │   - resolves dependency graph                             │
              │   - creates one Gitea repo per Application                │
              │   - commits initial manifests to develop/staging/main     │
              └──────────────────────────────────────────────────────────┘
                                     │
                                     ▼
              ┌──────────────────────────────────────────────────────────┐
              │  Application Gitea repo: {org}/{app}                      │
              │  (FQDN form per NAMING §11.2 — one repo per Application)  │
              │  ────────────────────────────────────────────────────────  │
              │  branches: develop → dev env, staging → stg, main → prod  │
              │  ────────────────────────────────────────────────────────  │
              │  kustomization.yaml      ← root Flux Kustomization         │
              │  values.yaml             ← base values                     │
              │  overlays/               ← per-env overlays                │
              │    dev/values.yaml                                         │
              │    stg/values.yaml                                         │
              │    prod/values.yaml                                        │
              │  secrets/                ← ExternalSecret refs (no plain)  │
              │  CODEOWNERS              ← team / approver list            │
              │                                                            │
              │  EnvironmentPolicy lives separately in the system Gitea   │
              │  Org: system/catalyst-config/policies/{org}-{env}-policy   │
              └──────────────────────────────────────────────────────────┘
                                     │
                                     ▼ (Gitea webhook → projector → annotate)
              ┌──────────────────────────────────────────────────────────┐
              │  Flux in vcluster {org}                                  │
              │   - N GitRepository sources, one per App repo            │
              │   - each watching the env-appropriate branch              │
              │   - kustomize-controller applies to per-App namespaces   │
              │   - helm-controller renders Helm-based Blueprints        │
              └──────────────────────────────────────────────────────────┘
                                     │
                  ┌──────────────────┴────────────────────┐
                  ▼                                        ▼
        K8s Application workloads                 Crossplane Claims
        (Deployments, Services,                  (Hetzner servers, DNS records,
         Pods, Secrets via ESO)                   S3 buckets, Cloudflare Workers)
                                                          │
                                                          ▼
                                              Crossplane Compositions
                                              fan out to provider APIs

Crossplane is the only IaC. Users never write Crossplane Compositions in their Application configs. Blueprint authors do — when a Blueprint declares "needs an external Postgres," that becomes a Crossplane Claim under the hood. Advanced users (corporate sovereign-admins, OpenOva engineers) can author and contribute Crossplane Compositions as Blueprints. End users see "needs a database, pick existing or new" in the UI.

---

5. Read side: CQRS via JetStream → projector → console

┌────────────────────┐     ┌────────────────────┐     ┌──────────────────┐
│ k8s informers      │     │ Flux events        │     │ Gitea webhooks   │
│ (one per vcluster) │     │ (per vcluster)     │     │ (per Sovereign)  │
└─────────┬──────────┘     └─────────┬──────────┘     └─────────┬────────┘
          │                          │                          │
          ▼                          ▼                          ▼
   ┌────────────────────────────────────────────────────────────────────┐
   │  NATS JetStream                                                    │
   │  Account isolation: one NATS Account per Organization.             │
   │  Subject prefix scoped per Environment (where <env> = {org}-{env_type}): │
   │     ws.<env>.k8s.<obj-kind>.<ns>.<name>                            │
   │     ws.<env>.flux.<kustomization>                                  │
   │     ws.<env>.git.<commit-hash>                                     │
   │     ws.<env>.crossplane.<resource>                                 │
   └────────────────────────────────────────────────────────────────────┘
                                  │
                                  ▼ durable consumer per env partition
   ┌────────────────────────────────────────────────────────────────────┐
   │  projector                                                         │
   │   - consumes events                                                │
   │   - rebuilds per-object state                                      │
   │   - writes to JetStream KV: ws-<env>-state/<kind>/<name>           │
   │   - fans out SSE to subscribed console clients                     │
   │   - authorizes by JWT claim {environment, org, role}               │
   │   - serves REST/GraphQL snapshot read API                          │
   └────────────────────────────────────────────────────────────────────┘
                                  │
                                  ▼
                       ┌────────────────────┐
                       │  Catalyst console  │
                       └────────────────────┘

One spine (JetStream), one read model (JetStream KV), one consumer (projector), one stream (SSE).

The console never talks to k8s API or Git directly. This is the architectural lock that prevents the "App says installed in one tab, failed in another tab" class of bug. Both tabs read the same JetStream KV snapshot served by the same projector replica.

JetStream replaces the older Redpanda + Valkey pairing in the control plane: NATS is Apache 2.0 (no BSL risk), has native KV (fewer moving parts), and native multi-tenant Accounts (cleaner per-Org isolation). Application-layer event needs (e.g. TalentMesh's voice pipeline) remain free to choose Redpanda, Kafka, NATS, or anything else — that's an Application-level decision, not a control-plane one.

---

6. Identity and secrets

Two separate identity systems for two separate purposes:

Subject	System	Lifetime	Purpose
Workloads (every Pod)	SPIFFE/SPIRE → SVID (mTLS cert)	5 min, auto-rotated	Pod-to-Pod auth, Pod-to-OpenBao auth, Pod-to-NATS auth
Users (every human)	Keycloak → JWT	15 min access / 30 day refresh	UI auth, API auth

Secrets flow:

            OpenBao (per-region, independent Raft cluster)
                  │
                  │ (workload requests via SPIFFE SVID)
                  ▼
            ESO ExternalSecret CR (in Git, references OpenBao path)
                  │
                  ▼
            K8s Secret (versioned, reloader watches for hash change)
                  │
                  ▼
            Pod (env var or mounted file)

Multi-region: each region runs its own 3-node Raft OpenBao cluster. No stretched cluster. Cross-region async perf replication for read availability and DR. A region failure does not require any other region to do anything.

Keycloak topology depends on Sovereign type:

• SME-style (per-organization): minimal single-replica Keycloak per Org, sized for hundreds of users. Embedded H2 or sqlite. Each Org's Keycloak is independent; failure does not affect other Orgs.
• Corporate-style (shared-sovereign): one HA Keycloak for the entire Sovereign, federating to the parent corporation's identity provider (Azure AD, Okta).

See SECURITY.md for full credential rotation and identity flow.

---

7. The user-facing surfaces

Three first-class surfaces. No fourth.

7.1 UI (the Catalyst console)

Default. Most users never leave it. Three depths the user can switch between:

• Form view — one Application page, fields driven by configSchema. Default for SME.
• Advanced view — same page with topology, secrets, observability, history, manifest tabs. Default for corporate.
• IaC editor view — in-browser Monaco editing the Application's Gitea repo with Blueprint-schema validation, live diff, commit-on-save. Toggle, not modal.

All three commit to the same Application Gitea repo (one repo per App, branches develop/staging/main mapping to dev/stg/prod). The Application card is the user's primary handle — see PERSONAS-AND-JOURNEYS.md.

7.2 Git

Direct push or pull-request to the Application's Gitea repo (one repo per App), or to shared-blueprints for Org-private Blueprints, or to catalog-sovereign for Sovereign-curated private Blueprints.

Identical write semantics as the UI. Both end up as commits on the App's repo branches. EnvironmentPolicy (PR approvals, soak, change windows) applies regardless of the surface — the policy CR lives in the system Gitea Org and is matched by Org+env_type at projector enforcement time.

7.3 API (REST + GraphQL)

For integrations, not for primary IaC authoring.

Use cases:

• A bank's existing Backstage portal queries Catalyst to show Environments and Applications.
• A change-management tool (ServiceNow, JIRA) triggers Application installs based on a ticket.
• A monitoring/auditing tool exports state for compliance reports.

The API exposes the same operations the console performs. It is not an IaC authoring layer in the Terraform-cloud sense. We do not ship a Terraform provider, a Pulumi SDK, or any other "declare desired state through us" surface — the Application Gitea repo is that surface.

7.4 What's deliberately NOT a surface

• kubectl — useful for debugging inside one's own vcluster; never a configuration mechanism.
• A standalone CLI for production changes — Catalyst may expose a small read-only debug CLI in the future; not authoritative for installs/promotions.
• Terraform / Pulumi — Crossplane covers non-K8s; it is platform plumbing, not user-facing.

---

8. Promotion across Environments

Promotion is not a separate engine or a chain object. Because each Application is a single Gitea repo with branches mapping to env_types, promotion is the simple act of opening a PR from the lower-env branch to the higher-env branch (e.g. staging → main to promote stg → prod), plus a policy gating the destination branch.

Blueprint detail page in console:

  bp-wordpress @ available 1.4.0
  ─────────────────────────────────────────────────
  Applications using this Blueprint in your Org (4)

  Application       Environment        Version    Status
  ──────────────────────────────────────────────────────
  marketing-site    acme-dev           1.4.0      ● Running   [Open]
  marketing-site    acme-stg           1.3.0      ● Running   [Open]
  marketing-site    acme-prod          1.2.0      ● Running   [Open]
  blog              acme-prod          1.2.0      ● Running   [Open]

  [ + Install in another Environment ]
  [ Compare versions ]

From marketing-site in acme-stg, the user clicks "Promote to acme-prod". Catalyst opens a Gitea PR from the staging branch to the main branch in the same marketing-site Application repo. The destination Environment's EnvironmentPolicy CR (in the system Gitea Org, matched by appliesTo.environments: [acme-prod]) supplies the approvers, soak duration, change window, and RE-score gate that apply to the PR. On merge, the Flux instance in the acme-prod vcluster (which watches the main branch) reconciles. Done.

# Lives at: system/catalyst-config/policies/acme-prod-policy.yaml
# (in the Sovereign-admin's `system` Gitea Org)
apiVersion: catalyst.openova.io/v1alpha1
kind: EnvironmentPolicy
metadata:
  name: acme-prod-policy
  namespace: catalyst-system
spec:
  appliesTo:
    environments: [acme-prod]
  rules:
    - kind: pr-required
      approvers: [team-platform, team-security]
      minApprovals: 2
    - kind: re-score-gate
      minScore: 80
      severity: blocking
    - kind: soak
      sourceEnvironment: acme-stg
      duration: 72h
    - kind: change-window
      cron: "0 14 * * 2,4"  # Tue/Thu 14:00
      duration: 2h

The policy lives in the Sovereign-admin's system Gitea Org and applies uniformly to every Application in the destination Environment, regardless of who initiated the change (UI, Git, API). The same CR shape is used for SME and corporate Sovereigns — only the field values differ (e.g. minApprovals: 1 for SMEs with a single org-admin, minApprovals: 2-3 for corporate teams).

---

9. Multi-Application linkage (the dependency tree)

A Blueprint can declare dependencies on other Blueprints:

apiVersion: catalyst.openova.io/v1alpha1
kind: Blueprint
metadata:
  name: bp-wordpress
  version: 1.3.0
spec:
  configSchema: …
  depends:
    - blueprint: bp-postgres
      version: ^1.4
      alias: db
      when: "{{ .config.postgres.mode == 'embedded' }}"
      values:
        databases: ["{{ .application.name }}"]

When a User installs marketing-site from bp-wordpress:

1. Catalog-svc flattens the dependency tree.
2. Console asks: "WordPress requires Postgres. Use an existing Postgres Application or create a new dedicated one?" — querying projector for existing bp-postgres Applications in this Org.
3. Provisioning service composes an InstallPlan: either one Application (marketing-site) referencing an existing postgres Application, or two Applications (marketing-site + marketing-site-postgres).
4. Gitea creates one or two repos under the Org's Gitea Org (e.g. acme-pharmacy/marketing-site + acme-pharmacy/marketing-site-postgres), each with develop/staging/main branches and initial manifests.
5. Flux in the Org's vcluster picks up new GitRepository sources and reconciles in dependency order via cross-repo Kustomization.dependsOn edges.

Every Application is its own Gitea repo and its own Flux Kustomization. The dependency graph is materialized as dependsOn edges between Kustomizations (which are namespaced CRs in the vcluster, regardless of which Gitea repo each Kustomization was sourced from), computed at install time from the Blueprint's depends declaration.

---

10. Provisioning a Sovereign

Phase 0  Bootstrap (one-shot, runs from catalyst-provisioner.openova.io)
─────────────────────────────────────────────────────────────────────
1. OpenTofu provisions: VPC, host nodes, load balancers, object storage
   on the target cloud provider (Hetzner / AWS / etc.). DNS is NOT
   written here — it flows through the PowerDNS / pool-domain-manager
   plane (see step 3 below + docs/PLATFORM-POWERDNS.md).
2. Bootstrap kit installs in order:
   a. Cilium (CNI + Gateway API)              ← network must come first
   b. cert-manager                            ← TLS for everything below
   c. Flux (host-level)                       ← GitOps engine
   d. Crossplane + provider config            ← cloud resource control plane
   e. Sealed Secrets (transient, only for bootstrap secrets)
   f. SPIRE server + agent                    ← workload identity
   g. NATS JetStream cluster (3 nodes)
   h. OpenBao cluster (3 nodes, region-local Raft)
   i. Keycloak (per `keycloakTopology` choice)
   j. Gitea (with public Blueprint mirror seeded)
   k. PowerDNS (bp-powerdns) + dnsdist        ← per-Sovereign authoritative
                                                DNS zone, DNSSEC, lua-records
   l. Catalyst control plane (umbrella Blueprint: bp-catalyst-platform)
3. Pool-domain-manager (running on the OpenOva-run Catalyst-Zero, NOT
   on the new Sovereign) calls `/v1/commit`: creates the per-Sovereign
   PowerDNS zone, writes the canonical 6-record set via the PowerDNS
   REST API, and updates the parent-zone NS delegation via the matching
   registrar adapter (Cloudflare / Namecheap / GoDaddy / OVH / Dynadot)
   — see docs/SOVEREIGN-PROVISIONING.md §3 + docs/PLATFORM-POWERDNS.md.

Phase 1  Hand-off (~5 minutes after Phase 0 starts)
─────────────────────────────────────────────────────────────────────
Crossplane in the new Sovereign adopts management of further
infrastructure. OpenTofu state is archived. Bootstrap kit is no
longer in the runtime path.

Phase 2  Day-1 setup
─────────────────────────────────────────────────────────────────────
First sovereign-admin logs into the console; configures cert-manager
issuers, backup destinations, optional federation; onboards the first
Organization and creates its first Environment.

Phase 3  Steady-state operation
─────────────────────────────────────────────────────────────────────
Catalyst is fully autonomous. catalyst-provisioner.openova.io remains
online indefinitely as the entry point for future Sovereign
provisioning runs — but the existing Sovereign no longer depends on
it at runtime.

See SOVEREIGN-PROVISIONING.md for the full procedure (this is the canonical reference for phase semantics).

---

11. Catalyst-on-Catalyst (dogfooding)

Every component in the Catalyst control plane is itself published as a Blueprint:

bp-catalyst-platform                 ← umbrella
├── depends: bp-catalyst-console
├── depends: bp-catalyst-marketplace
├── depends: bp-catalyst-admin
├── depends: bp-catalyst-catalog-svc
├── depends: bp-catalyst-projector
├── depends: bp-catalyst-provisioning
├── depends: bp-catalyst-environment-controller
├── depends: bp-catalyst-blueprint-controller
├── depends: bp-catalyst-billing
├── depends: bp-catalyst-gitea            ← per-Sovereign Git server
├── depends: bp-catalyst-nats-jetstream   ← event spine + KV
├── depends: bp-catalyst-openbao          ← secret backend
├── depends: bp-catalyst-keycloak         ← user identity
├── depends: bp-catalyst-spire            ← workload identity
└── depends: bp-catalyst-observability    ← OTel + Grafana stack

(Cilium, Flux, Crossplane, Cert-manager, Kyverno, Harbor, External-Secrets, Reloader, Falco, Sigstore, Syft+Grype, PowerDNS are per-host-cluster infrastructure, not Catalyst control-plane components — see PLATFORM-TECH-STACK.md §1. They get installed once per host cluster, before Catalyst itself. The pool-domain-manager (PDM) is deployed on the OpenOva-run Catalyst-Zero only — it is part of the bootstrap surface, not the per-Sovereign control plane.)

Installing bp-catalyst-platform once gives you a working Sovereign. Same Blueprint installed on Hetzner = the openova Sovereign. Same Blueprint installed on AWS for a bank = that bank's Sovereign. Same Blueprint installed on Hetzner for a telco = the omantel Sovereign. One artifact. Zero divergence.

OpenOva's own customer Applications (Cortex, Fingate, Fabric, Relay, Specter, Axon) are similarly composite Blueprints that run on top of Catalyst — they are Applications inside the openova-public Environment of the openova Sovereign.

---

12. State-of-the-art principles applied

Pattern	Where it lives in this design
CQRS	Write side: Git → Flux → K8s. Read side: catalog-svc + projector.
GitOps as truth	Every state change is a commit. Rollback = git revert. Audit = git log.
Event sourcing	NATS JetStream is the durable event log. Projector replays for recovery.
CRD-driven control plane	Sovereign, Organization, Environment, Application, Blueprint, EnvironmentPolicy, SecretPolicy, Runbook — all CRDs. Controllers reconcile.
Multi-tenancy at OS layer	vcluster per Organization per host cluster — isolated K8s API + control plane per Org.
Crossplane for non-K8s	All cloud-side resources via Compositions. Users never see Crossplane.
OCI artifacts for software	Blueprints are signed OCI manifests, cosigned, SBOMed.
CloudEvents-shaped envelopes	Standard event format on JetStream subjects.
OpenTelemetry first-class	All Catalyst services emit traces; every Blueprint inherits OTel by default.
Policy as code	Kyverno policies in Catalyst block out-of-policy commits and out-of-policy K8s resources.
Supply chain security	cosign signing, SLSA-3 build provenance, Syft+Grype SBOM, Trivy scans, Falco runtime.
JSON Schema for config	Console form is generated from Blueprint configSchema. No hand-written forms.
Pull-based updates	Each Sovereign mirrors the public Blueprint catalog on its own schedule. Air-gap-ready by construction.
Workload identity	SPIFFE/SPIRE SVIDs replace static service-account credentials end-to-end.
Independent failure domains	OpenBao Raft per region. vcluster per Org. Keycloak per Org (SME) or per Sovereign (corporate).

---

13. Open Application Model influence

The Blueprint shape is influenced by — but not identical to — OAM:

OAM term	Catalyst equivalent
Application	Blueprint with card.category=composite
Component	Blueprint (single-purpose)
Trait	Blueprint overlay (e.g. overlays/small, overlays/medium, overlays/large)
Scope	Environment + Placement

We are not a strict OAM implementation. We borrow the layered composition idea but use Kubernetes-native primitives (Kustomize, Helm) rather than OAM-specific machinery — because Flux, Crossplane, and the K8s ecosystem are the runtime, and inventing a new layer adds no value.

---

14. Read further

• GLOSSARY.md — every term defined.
• NAMING-CONVENTION.md — every name's pattern.
• PERSONAS-AND-JOURNEYS.md — who uses each surface and how.
• SECURITY.md — identity, secrets, rotation in detail.
• SOVEREIGN-PROVISIONING.md — bringing a Sovereign online.
• BLUEPRINT-AUTHORING.md — writing Blueprints (including Crossplane Compositions for advanced users).
• PLATFORM-TECH-STACK.md — every component's role in Catalyst.
• SRE.md — operating a Sovereign.