# clusters/

Flux entrypoints and the environment-overlay model (**R-ENV-02**, **R-GITOPS-01/02/03**).

Governing spec: [`docs/05-gitops-and-delivery.md`](../../home-network-k3s/docs/05-gitops-and-delivery.md),
[`docs/02-environments-and-provisioning.md`](../../home-network-k3s/docs/02-environments-and-provisioning.md),
[ADR-0004 (Flux)](../../home-network-k3s/decisions/adr-0004-gitops-flux.md).

> Phase 0 scaffolding only. These are structurally-correct stubs. **No cluster exists** — nothing
> here reconciles until WS-INFRA delivers a cluster and bootstraps Flux (roadmap Phase 1).

## Layout — base + overlay (never fork the base)

```
clusters/
  base/                 shared Flux objects (one authoring, both environments)
    flux-system.yaml    GitRepository — the reconciliation source (bootstrap → Gitea)
    platform.yaml       Flux Kustomization → ./platform   (reconciles first)
    apps.yaml           Flux Kustomization → ./apps        (dependsOn platform)
    cluster-vars.yaml   ConfigMap of overlay knobs (BASE defaults)
    kustomization.yaml
  dev/                  ACTIVE build target — patches cluster-vars with dev values only
    kustomization.yaml
  prod/                 DESIGN-ONLY until roadmap Phase 7 — patches cluster-vars with prod values only
    kustomization.yaml
```

## How the overlay model satisfies R-ENV-02

The base authors the reconciliation graph **once**. `platform.yaml` and `apps.yaml` (Flux
`Kustomization`s) both declare `postBuild.substituteFrom` the `cluster-vars` ConfigMap. Platform and
app manifests use `${TOKEN}` placeholders for every value that legitimately differs between
environments (issuer, replica counts, storage sizes, retention, node placement).

**`clusters/dev` and `clusters/prod` differ ONLY by the values they patch into `cluster-vars`** —
they add no resources of their own and never copy/fork a base manifest. Promotion to prod
([`docs/02`](../../home-network-k3s/docs/02-environments-and-provisioning.md)) is a change to the
prod overlay's variables, nothing else.

## How Flux is pointed at an environment

`flux bootstrap` (run by WS-INFRA in Phase 1) targets one environment's path per cluster:

```
# dev cluster
flux bootstrap ... --path=clusters/dev
# prod cluster (Phase 7 only — design-only until then)
flux bootstrap ... --path=clusters/prod
```

Bootstrap materializes the `flux-system` `Kustomization` that renders the chosen overlay, which pulls
in `base/` and applies the env-scoped `cluster-vars`.

## Reconciliation order

```
GitRepository (flux-system)
        │
        ▼
Kustomization: platform  (./platform, substituteFrom cluster-vars)
        │  healthy
        ▼
Kustomization: apps      (./apps, dependsOn platform, substituteFrom cluster-vars)
```

`apps` `dependsOn` `platform` so CNI/storage/TLS/DNS/gateway exist before any workload reconciles.

## TODOs (later phases — do not action in Phase 0)

- **Source cutover (WS-GITOPS, Phase 6):** `base/flux-system.yaml` currently points at the bootstrap
  source. After Gitea is onboarded, repoint `spec.url` to `gitea.home.keithjackson.dev` and keep an
  off-cluster mirror (spec `docs/05` "Source-of-truth", `CONTRIBUTING.md`).
- **SOPS decryption (WS-SEC, Phase 1):** add `spec.decryption.provider: sops` (age secret name only,
  never plaintext) to the platform/apps Kustomizations once the age key is bootstrapped
  ([ADR-0007](../../home-network-k3s/decisions/adr-0007-secrets-sops-age.md)).
- **Split ordered Flux Kustomizations** if intra-platform ordering needs to be explicit (e.g. a
  separate `cilium`/`longhorn` Kustomization others `dependsOn`).
</content>