phase2-prep: per-component no-secret rollout + component hardening (author-first)

Prep only — nothing deployed; running cluster untouched.

Reconciliation graph (operator-approved Option A): author clusters/dev/rollout/
= 4 per-component Flux Kustomizations (kyverno->cilium->longhorn->monitoring,
monitoring dependsOn longhorn). Dev overlay $patch:delete's the monolithic base
platform/apps and adds ./rollout, so only the no-secret tier reconciles; the
secret-blocked components are simply not created until hand-offs arrive. The
no-secret tier carries no SOPS content, so it needs no sops-age key. prod is
untouched (still builds the monolith). Convergence path coded in (delete rollout/
+ the two deletes) — R-ENV-02 divergence flagged for architect review.

Component hardening via cluster-vars (prod keeps strict posture):
- KYVERNO_VALIDATION_ACTION Enforce->Audit(dev), _WEBHOOK_FAILURE_POLICY
  Fail->Ignore(dev), _ADMISSION_REPLICAS 3->1(dev); webhook namespaceSelector
  excludes system+platform namespaces.
- MONITORING_STORAGE_CLASS var; GRAFANA_ADMIN_SECRET var (dev ''=chart default);
  Alertmanager SMTP/secret deferred to Phase-4 with verbatim re-enable markers.

Cilium parity verified against the live CNI (no-op adopt). Validated:
kubectl kustomize dev/prod/all-components, envsubst->YAML parse, make -C ci gate PASS.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

platform/kyverno/admission/helmrelease.yaml

@@ -34,18 +34,32 @@ spec:
     remediation:
       retries: 3
   values:
-    # HA admission controller so a single pod restart cannot open an enforcement gap.
+    # Admission controller replicas — cluster-vars knob (prod 3 / dev 1). HA so a single pod
+    # restart cannot open an enforcement gap; dev drops to 1 to save RAM during bootstrap.
     admissionController:
-      replicas: 3
+      replicas: ${KYVERNO_ADMISSION_REPLICAS}
     backgroundController:
       enabled: true               # needed for generate (default-deny baseline) + sync
     reportsController:
       enabled: true
     cleanupController:
       enabled: true
-    # Fail-CLOSED: if the webhook is unreachable, reject rather than silently admit
-    # non-conforming resources (coordination-protocol.md #8). Tune per-resource in
-    # the policies' webhook config if a bootstrap deadlock appears.
+    # Webhook failure policy — cluster-vars knob (prod Fail / dev Ignore). Fail is fail-CLOSED
+    # (reject rather than silently admit when the webhook is unreachable, coordination-protocol.md
+    # #8); dev uses Ignore (fail-open) so a cold/unhealthy Kyverno cannot brick admission during
+    # bootstrap. The namespaceSelector ALSO excludes system + platform namespaces at the webhook
+    # layer — belt-and-suspenders: policies already scope to app-namespace=true, but this
+    # guarantees kube-system/flux-system/CNI/storage/monitoring admission never routes to Kyverno.
     config:
       webhooks:
-        - failurePolicy: Fail
+        - failurePolicy: ${KYVERNO_WEBHOOK_FAILURE_POLICY}
+          namespaceSelector:
+            matchExpressions:
+              - key: kubernetes.io/metadata.name
+                operator: NotIn
+                values:
+                  - kube-system
+                  - flux-system
+                  - kyverno
+                  - longhorn-system
+                  - monitoring

platform/kyverno/admission/secret-provenance.yaml

@@ -24,7 +24,7 @@ metadata:
     homelab.keithjackson.dev/requirements: R-SEC-01
     homelab.keithjackson.dev/scope: admission-only
 spec:
-  validationFailureAction: Enforce
+  validationFailureAction: ${KYVERNO_VALIDATION_ACTION}
   background: false
   rules:
     - name: secrets-must-be-flux-managed

platform/kyverno/policies/require-auth-mode-label.yaml

@@ -25,7 +25,7 @@ metadata:
       Pods in application namespaces must declare
       homelab.keithjackson.dev/auth-mode = oidc | forward-auth | native | none.
 spec:
-  validationFailureAction: Enforce
+  validationFailureAction: ${KYVERNO_VALIDATION_ACTION}
   background: true
   rules:
     - name: require-auth-mode

platform/kyverno/policies/require-egress-class-label.yaml

@@ -25,7 +25,7 @@ metadata:
       Pods in application namespaces must declare
       homelab.keithjackson.dev/egress-class = internet | vpn.
 spec:
-  validationFailureAction: Enforce
+  validationFailureAction: ${KYVERNO_VALIDATION_ACTION}
   background: true
   rules:
     - name: require-egress-class

platform/kyverno/policies/restrict-host-namespaces.yaml

@@ -24,7 +24,7 @@ metadata:
       Application-namespace pods must not use hostNetwork/hostPID/hostIPC (which
       bypass default-deny) or run privileged containers.
 spec:
-  validationFailureAction: Enforce
+  validationFailureAction: ${KYVERNO_VALIDATION_ACTION}
   background: true
   rules:
     - name: disallow-host-namespaces

platform/kyverno/policies/validate-default-deny-shape.yaml

@@ -20,7 +20,7 @@ metadata:
       to include both Ingress and Egress. Rejects a baseline that silently leaves
       a direction open.
 spec:
-  validationFailureAction: Enforce
+  validationFailureAction: ${KYVERNO_VALIDATION_ACTION}
   background: true
   rules:
     - name: baseline-must-deny-both-directions