Files
home-network-k3s-impl/clusters/base/platform.yaml
jakman85andClaude Opus 5 666a60776a fix(flux): close the substitution race — platform dependsOn root + strict substitution (P0/P1)
P0 — clusters/base/platform.yaml gains `dependsOn: [flux-system]`. This is the actual fix
for the incident, not the feature gate. Verified against kustomize-controller v1.4.0
`kustomization_controller.go :: checkDependencies` (our version): dependsOn is REVISION-
gated, not merely Ready-gated — when the dependency shares a GitRepository, the dependent
cannot reconcile revision N until the dependency has APPLIED revision N. Applying revision
N is exactly what writes a newly-added cluster-vars knob.

Graph verified mechanically, not by eye: built clusters/dev and clusters/prod and walked
the resulting objects. `platform` was the ONLY Kustomization without a dependsOn, and all
11 substituting Kustomizations chain transitively through it (platform-config -> platform;
the waves, apps-vms, oauth2-proxy, headlamp, homepage, crafty, velero -> platform-config).
The "not chaining through platform" set is EMPTY, so this one edge protects the whole
graph. DFS over the full edge set after the edit: no cycles. The root (clusters/dev/
sync.yaml) runs wait: false, which is what makes the edge deadlock-free — it reaches Ready
on apply success without health-gating its children.

Accepted trade-off, documented in-file: the root becomes a gate. A malformed manifest
anywhere under clusters/<env> — including clusters/base — now stalls platform and
everything downstream, where today it would not. Fail-closed, per doctrine.

P1 — StrictPostBuildSubstitutions. MY PREMISE WAS WRONG about where this belongs and it
matters: this repo deliberately does NOT use `flux bootstrap` (see bootstrap/flux/README).
There is no gotk-components.yaml in git, and the live kustomize-controller Deployment
carries NO Flux ownership labels — it was installed imperatively by `flux install` from
bootstrap.sh and is not in Flux's inventory. `flux-system` self-manages the CR graph, NOT
the controllers. Nothing under clusters/** can reach a controller flag.

So it uses Flux's documented mechanism for hand-installed clusters: a new
bootstrap/flux/components/kustomization.yaml wrapping `gotk-components.yaml` with a
JSON-6902 patch appending --feature-gates=StrictPostBuildSubstitutions=true to
kustomize-controller. JSON-6902 `add /args/-` deliberately, NOT strategic merge — a
container's args is atomic and a merge patch would replace all five install-generated
args. bootstrap.sh step 1 now renders (`flux install --export` into a temp dir, apply the
patch, ASSERT the gate string is present so a future Flux bump that breaks the patch
target fails loudly) then applies. FLUX_INSTALL_PLAIN=1 is a loud escape hatch. Nothing is
vendored, so components can never drift from the pinned FLUX_VERSION.

Rejected: vendoring gotk-components.yaml under the root's path (the root's prune: true
would put Flux's own controllers and CRDs in a prune inventory), and shipping a partial
Deployment as a Flux-managed resource (a future prune would delete kustomize-controller).

ROLLOUT ORDER MATTERS. P0 arrives automatically on the next reconcile. P1 does NOT arrive
on a git push — the controller Deployment is outside Flux's inventory, so an operator must
re-run bootstrap.sh step 1, which restarts kustomize-controller (~10-20s; Flux is
level-triggered so an interrupted reconcile is simply retried). P0 must be reconciled
BEFORE P1 is rolled out: with the gate on but the ordering edge absent, the same race
turns a transient empty render into a transient hard Kustomization failure.

ALSO FIXES A PHASE-7 BLOCKER THIS CHANGE WOULD OTHERWISE HAVE CREATED. clusters/prod had
no root Kustomization — dev/sync.yaml even carried the note "a prod overlay needs its own
sync.yaml -> ./clusters/prod". With the new dependsOn, a prod bootstrap would have left
platform blocked forever on a flux-system Kustomization that does not exist, and nothing
downstream would ever reconcile. clusters/prod/sync.yaml is now authored, mirroring dev.

Two further prod-overlay gaps found and DOCUMENTED, not guessed (PROD-PROVISIONING §7):
prod has no SOPS `decryption` patch (every encrypted Secret would fail to decrypt — needs
the prod age-key decision, a security choice not a copy), and no GitRepository source URL
patch (needs a decision on whether prod tracks the same branch as dev, which would make a
dev-facing merge reconcile prod).

Substitution gate re-run: check OK, 102 assertions, 0 hazards. Gate: MERGE GATE: PASS.

Serves: R-ENV-02, R-GITOPS-01, R-PLAT-01, R-ENV-03.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
2026-09-01 01:45:04 -05:00

60 lines
3.3 KiB
YAML

---
# Flux Kustomization: PLATFORM services (cluster-wide). Reconciles ./platform.
# Phase 0 STUB. Realizes R-GITOPS-01/03 (pull-based reconcile + drift correction) and
# R-ENV-02 (env differences supplied ONLY via substituteFrom cluster-vars).
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
name: platform
namespace: flux-system
spec:
interval: 10m
retryInterval: 2m
timeout: 5m
prune: true # drift correction: delete resources removed from git (R-GITOPS-03)
wait: true # block `apps` until platform is healthy
# ORDERING FIX (2026-09-01 incident: a substitution race that failed OPEN broke Cilium).
#
# `cluster-vars` — the ConfigMap every substituting Kustomization reads — is APPLIED by the root
# `flux-system` Kustomization (clusters/<env>/sync.yaml), not by this one. Without an edge here,
# `platform` could render a manifest from revision N against the revision N-1 `cluster-vars`, so a
# NEWLY ADDED knob was undefined and (non-strict substitution) silently became the EMPTY STRING.
# That is how `k8sServiceHost: ""` reached the Cilium HelmRelease.
#
# `dependsOn` is REVISION-gated, not merely Ready-gated (verified against
# kustomize-controller v1.4.0 `kustomization_controller.go :: checkDependencies`, our version):
# when the dependency shares a GitRepository with the dependent, the dependent cannot reconcile
# revision N until the dependency has APPLIED revision N. Applying revision N is exactly what
# writes a newly-added `cluster-vars` knob — so this one edge closes the race.
#
# `platform` is the ONLY Kustomization in the graph with no `dependsOn`; every other substituting
# consumer (platform-config, apps-wave-0/1/2, apps-vms, oauth2-proxy, headlamp, homepage, crafty,
# velero) chains transitively through it. One edge therefore protects the whole graph.
#
# TRADE-OFF — READ THIS BEFORE YOU CURSE IT: the root is now a GATE. A malformed manifest
# ANYWHERE under the root's path (clusters/<env>, which includes clusters/base) fails the root
# Kustomization and therefore stops `platform` and EVERYTHING downstream, where before this edge
# the rest of the graph would have kept reconciling. That is deliberate and fail-closed: a broken
# entrypoint should stop the line, not let consumers render against a half-applied variable set.
# No deadlock risk — the root runs `wait: false`, so it reaches Ready on APPLY success and never
# health-gates its own children (see clusters/dev/sync.yaml).
dependsOn:
- name: flux-system # the ROOT Kustomization (sync.yaml) that applies cluster-vars
sourceRef:
kind: GitRepository
name: flux-system
path: ./platform
# R-ENV-02: the ONLY place environment differences enter platform manifests.
# dev/prod overlays patch the cluster-vars ConfigMap; the base manifests are never forked.
postBuild:
substituteFrom:
- kind: ConfigMap
name: cluster-vars
# TODO(WS-SEC, Phase 1): enable SOPS decryption once the age key exists (ADR-0007).
# decryption:
# provider: sops
# secretRef:
# name: sops-age
# TODO(PM): the top-level ./platform/kustomization.yaml must include platform/kyverno/
# (owned by the policy engineer, WS-TEST). See platform/README.md integration TODO.