# 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-wave-0.yaml Flux Kustomization → ./apps/wave-0 (dependsOn platform-config) apps-wave-1.yaml Flux Kustomization → ./apps/wave-1 (dependsOn apps-wave-0) apps-wave-2.yaml Flux Kustomization → ./apps/wave-N (dependsOn apps-wave-N-1) 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 the app-wave Kustomizations (`apps-wave-0/1/2.yaml` — the single `apps.yaml` was retired; `apps-vms.yaml` deliberately omits it, see below) declare `postBuild.substituteFrom` the `cluster-vars` ConfigMap. Platform and app manifests use `${TOKEN}` placeholders for every value that legitimately differs between environments (issuer, replica counts, storage sizes, retention, node placement). **`clusters/dev` and `clusters/prod` differ ONLY by the values they patch into `cluster-vars`** — they add no resources of their own and never copy/fork a base manifest. Promotion to prod ([`docs/02`](../../home-network-k3s/docs/02-environments-and-provisioning.md)) is a change to the prod overlay's variables, nothing else. ### LAN addressing is a knob, not a literal (fixed 2026-08-31) Until 2026-08-31 the base manifests hardcoded the **dev** LAN: the k3s API host Cilium dials, the Cilium LB IP pool range, the pinned crafty/unifi L4 VIPs and the off-cluster S3 backup endpoint. That broke R-ENV-02 outright — `clusters/prod` would have rendered dev addresses (192.168.1.x) onto the prod LAN (192.168.2.x). They are now the `cluster-vars` "LAN addressing" block (`K3S_API_HOST`, `CILIUM_LB_POOL_START`/`_STOP`, `UNIFI_L4_VIP`, `CRAFTY_L4_VIP`, `S3_BACKUP_ENDPOINT`, alongside the pre-existing `GATEWAY_VIP`), set explicitly by BOTH overlays. Two rules when touching that block: 1. **Substitution coverage.** A `${TOKEN}` only resolves in a path whose Flux Kustomization declares `postBuild.substituteFrom: cluster-vars`; anywhere else the literal string `${TOKEN}` ships to the cluster. `apps-vms` was the one path without it and now has it — which means every shell `${...}` in a VM manifest's cloud-init must be escaped `$${...}` (see `clusters/base/apps-vms.yaml` for the full envsubst escape contract). 2. **`GATEWAY_VIP` must be inside `CILIUM_LB_POOL_START..STOP`,** and in practice equal to START: the `shared` Gateway pins no address, so Cilium LB-IPAM gives it the pool's first free IP while split-horizon CoreDNS answers with `${GATEWAY_VIP}`. A VIP outside the pool blackholes in-cluster hairpin traffic while the Gateway still looks healthy. Values the operator has not decided are `TBD-PROD-*` placeholders, not guesses: prod inherits the DEV base defaults if an overlay op is simply omitted, so an invalid value that fails loudly is strictly safer than a plausible one that quietly comes up on the wrong network. ## 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-wave-0 (./apps/wave-0, dependsOn platform-config, substituteFrom cluster-vars) │ healthy ▼ Kustomization: apps-wave-1 (./apps/wave-1, dependsOn apps-wave-0) │ healthy ▼ Kustomization: apps-wave-N (./apps/wave-N, dependsOn apps-wave-N-1) ``` Wave 0 `dependsOn` `platform-config` (transitively `platform`) so CNI/storage/TLS/DNS/gateway exist before any workload reconciles. The app tier is split into dependency-ordered WAVES (`catalog/render.py --emit-waves`): each `apps-wave-` health-gates (wait:true) ONLY its own wave, so a crashloop in a later wave can no longer stall an earlier wave or block new revisions. See [DESIGN-waves.md](../DESIGN-waves.md) for the wave table + cutover runbook. ## 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`).