feat(pihole): two replicas on different nodes, and fix a PVC mounted where pihole never writes

Phase 2 of making LAN DNS survive a node failure. Pihole was one pod on one
node; measured 2026-10-04, losing that node meant roughly 6-10 minutes with no
LAN resolution (tolerationSeconds 300 + NotReady detection + a Longhorn RWO
force-detach), while losing the node holding the pihole-dns L2 lease -- a
DIFFERENT node -- meant tens of seconds. Two of three nodes were single points
of failure with wildly different blast radii.

Adds `availability.replicas` to the ServiceDefinition schema (1.10.0). Intent
only; the mechanism is render.py's, documented in the renderer contract. 1 or
absent renders a Deployment exactly as before -- verified byte-identical across
the whole apps/ tree. >1 renders a StatefulSet (a longhorn PVC is RWO, so a
multi-replica Deployment never schedules the second pod), per-replica
volumeClaimTemplates, REQUIRED hostname anti-affinity, podManagementPolicy
Parallel, a minAvailable:1 PodDisruptionBudget, and an SLI that follows the
rendered kind (a Deployment-shaped rule against a StatefulSet absent()s forever).

Pinned by ~20 new --selftest assertions rather than a conformance change.

ALSO FIXES A LIVE BUG. Pihole's config PVC was mounted at the renderer default
/data/config, but pihole writes to /etc/pihole. Measured: /etc/pihole (7.1M --
gravity.db, pihole.toml, query DB) was on the OVERLAY, while the 2Gi Longhorn
volume held lost+found and 24K of nothing. So every restart discarded all state
and re-downloaded 72k gravity domains, and backup.policy has been backing up an
empty volume while reporting success. Fixed here because otherwise the new
per-replica volumes would hold nothing while state stayed ephemeral -- and
because persisting gravity.db is what makes a restart cheap.

The /etc/pihole mount is safe on the image's own evidence: start.sh is PID 1 as
uid 0 and chowns the directory recursively (no fsGroup needed), and it calls
migrate_gravity which creates the database when absent.

The gate caught a real regression on the first run: the wave-0 alert unit test
fed pihole a Deployment-shaped series. Updated; promtool SUCCESS.

Touches no sensitive paths, so this one needs no override.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

schemas/renderer-contract.md

@@ -161,6 +161,41 @@ platform must render, and cites the requirement each mapping satisfies. Changing
 - **Requirements:** **R-STATE-01** (rebuild survival), **R-STATE-02** (Longhorn replication),
   **R-STATE-04** (bulk tier). (docs/04)
 
+### `availability` (`replicas`) — workload kind, per-replica volumes, spreading, budget
+
+**Schema 1.10.0.** Availability INTENT. It names no Kubernetes object, no topology key and no
+budget — exactly like `hardware.gpu`, and for the same reason: the mechanism below should be
+replaceable without a catalog edit.
+
+- **Absent, or `replicas: 1`** → a **Deployment**, standalone PVC(s), `strategy: Recreate` when there
+  is storage, no PodDisruptionBudget. Byte-identical to pre-1.10.0 output, so every existing app is
+  untouched.
+- **`replicas: N > 1`** → all of the following, together:
+  | Rendered | Why |
+  |---|---|
+  | **StatefulSet** instead of Deployment | A longhorn PVC is **ReadWriteOnce**. One RWO claim cannot attach on two nodes, so a multi-replica Deployment does not degrade — the second pod never schedules. |
+  | longhorn storage becomes **`volumeClaimTemplates`** | Gives each replica its own claim (`<vol>-<svc>-<ordinal>`, e.g. `config-pihole-0`). The template's `metadata.name` **must** equal the pod volume name the container mounts. The standalone PVC is then **not** emitted — it would be an orphan nothing mounts. |
+  | `bulk` storage stays a **standalone PVC** | A bulk entry is a static, pre-bound NFS PV over data that already exists outside the cluster and is shared read-only. Per-replica copies are neither possible nor wanted. |
+  | **required** `podAntiAffinity` on `kubernetes.io/hostname` | `preferred` would let every replica land on one node and deliver none of the intended node-failure tolerance, while every object still reported healthy. |
+  | `podManagementPolicy: Parallel` | `OrderedReady` serialises first-boot work across replicas; `apps-wave-0` has `timeout: 5m`. There is no ordering requirement between replicas to protect. |
+  | **PodDisruptionBudget**, `minAvailable: 1` | Stops a *voluntary* disruption (node drain, upgrade) taking the last replica. It does nothing about a node dying — that is what the replica count and anti-affinity are for. Never rendered at `replicas: 1`, where `minAvailable: 1` would block every drain of that node forever. |
+  | `observability.livenessWorkload.kind` defaults to **`StatefulSet`** | The `up` SLI reads kube-state-metrics by workload kind. A Deployment-shaped rule against a StatefulSet `absent()`s forever — an alert that can never fire. Deriving the default means bumping the replica count cannot leave a stale rule behind. |
+
+**Two costs, both deliberate, neither hidden:**
+
+1. **N replicas need N schedulable nodes.** On a 3-node cluster, losing two nodes leaves a replica
+   `Pending`; since `apps-wave-0` is `wait: true` and `apps-wave-1` `dependsOn` it, that **stalls the
+   app tier**. That coincides with having lost etcd quorum on a 3-node control plane, so nothing is
+   reconciling at that point anyway — the stall is a symptom, not a new failure mode.
+2. **Only declare `> 1` for a service whose on-disk state is reproducible from git.** A replica with
+   a fresh volume comes up serving whatever it can bootstrap itself and nothing else. For pihole that
+   prerequisite was done first — the admin password and the adlists were declared in
+   `decisions/2026-10-04-pihole-declare-state.md` — because otherwise a second replica would have
+   served DNS while blocking nothing, with a different password.
+
+**Requirements:** R-PLAT-02 (the workload), R-STATE-01/02 (per-replica replicated volumes),
+R-OBS-01 (the SLI must follow the rendered kind).
+
 ### `hardware` (`gpu`) — host device capability
 - **The field is INTENT, never MECHANISM.** `hardware.gpu` is an **enum of capability classes**
   (today: `intel-quicksync`), not a device path, not a hostPath, not a resource request. The

schemas/servicedefinition.schema.json

@@ -2,7 +2,7 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "$id": "https://home.keithjackson.dev/schemas/servicedefinition.schema.json",
   "title": "ServiceDefinition",
-  "description": "Operator-facing onboarding contract for the home k3s + Longhorn platform. One ServiceDefinition per file under catalog/. Captures INTENT; the platform compiles it into concrete resources (see schemas/renderer-contract.md). Canonical source of truth: spec docs/13-service-catalog.md. Serves R-GITOPS-02; ties into R-NET-*, R-STATE-*, R-TLS-*, R-DNS-*, R-OBS-*, R-UPD-*, R-IDP-*. Schema version: 1.9.0 (adds optional `auth.apiRoutes` -- a per-service list of anchored path regexes the forward-auth oauth2-proxy sidecar answers with 401 instead of a 302 to Keycloak, rendered as one repeatable `--api-route` per entry. The `auth` block stays `additionalProperties: false`; this is one named, documented key, not an opened door. Without it there was NO per-app override hook at all, so the only way to answer an app's XHRs with 401 was a renderer-wide constant -- and the path shape is a property of the app: jackett's is `/api/` (33 x 302 vs 2 x 401 measured 2026-09-30, 4 of 6 POSTs answered by the proxy and never reaching the app), radarr's is `/signalr/` (232 x 302 measured 2026-10-01, every one a POST from a left-open browser tab that is never re-prompted), and pihole serves no `/api/` at all. Each entry must be anchored at `^/` and continue with literal path characters, because a too-broad regex turns a plain page load into a 401 and the service looks permanently broken to a logged-out user. Enforced on every gate run by ci/l0.sh's schema stage over catalog/*.yaml, by catalog/render.py refusing to render an unanchored entry, and by conformance/tests/l0-static/oauth2-proxy-api-routes-per-app)). 1.8.0 (adds optional `hardware` - a host HARDWARE CAPABILITY declaration for the container kind, currently one member: `hardware.gpu: intel-quicksync`, meaning the workload needs the host iGPU render device for hardware video transcode. It is an ENUM OF INTENT, not a device path: the renderer satisfies it today with just two things -- a /dev/dri hostPath volume (`DirectoryOrCreate`) and a read-write /dev/dri volumeMount on the app container -- and a later move to the Intel GPU device plugin is then a render.py change with no catalog edit. It sets NO podSecurityContext.supplementalGroups: measured in-container on prod 2026-09-30, the pms-docker cont-init hook adds the app user to the device's group inside the container and `s6-setuidgid` then REPLACES the process group list from /etc/group, discarding anything Kubernetes supplied, so such an entry would be inert and misleading. Renders NOTHING when absent, so every existing app stays byte-identical. Emits no privileged securityContext (Kyverno restrict-host-namespaces would reject it and it is not needed), no nodeSelector (node placement is a separate concern with its own justification) and no resource requests). 1.7.0 (no field changes; a MAPPING change to `exposure`, which had never had an effect on DNS. `exposure: internal` now renders ExternalDNS's own controller annotation onto every HTTPRoute it emits, set to a value other than `dns-controller`, so external-dns (v0.21.0, source/gateway.go -> annotations.IsControllerMismatch) skips the route before resolving any hostname and the service is INCAPABLE of producing a public record. Both docs/09 R-DNS-03 and schemas/renderer-contract.md already said `internal` renders no public DNS record; nothing enforced it, and six internal services -- jackett, pihole, qbittorrent, radarr, semaphore, sonarr -- were publishing `<name>.home.keithjackson.dev` into the PUBLIC Cloudflare zone answering with the RFC1918 Gateway VIP, which published the internal subnet and a full service inventory and made each name a DNS-rebind primitive. Enforced on every gate run by conformance/tests/l0-static/internal-services-publish-no-public-dns). 1.6.0 (splits `observability.metrics` from WHERE metrics live: adds optional `metricsEndpoint` (port/name/path/interval) and optional `livenessWorkload` (kind/name). `metrics: true` previously rendered a ServiceMonitor hardcoded to a port named `metrics` that no rendered Service ever defined, so all twelve app monitors discovered ZERO targets and every `up{job=...}` SLI was structurally inert on prod; a monitor is now rendered only from a declared `metricsEndpoint`, which also renders the Service port and the monitoring-namespace ingress allow, and the `up` SLI is expressed against kube-state-metrics -- a signal that exists for every workload without a per-app exporter. `livenessWorkload` names the object whose readiness IS the service, for the case where the running workload is not the one this SD renders). 1.5.0 (adds optional `inClusterClients` — additional in-cluster clients, named by NAMESPACE, admitted to a declared port of this service DIRECTLY, bypassing the shared Gateway. `ingressRoutes` admits only the Gateway proxy identity and `dependencies` only links catalog services, so a PLATFORM controller dialling a Service ClusterIP had no authorable form at all; that gap is what deadlocked proLine truncated
+  "description": "Operator-facing onboarding contract for the home k3s + Longhorn platform. One ServiceDefinition per file under catalog/. Captures INTENT; the platform compiles it into concrete resources (see schemas/renderer-contract.md). Canonical source of truth: spec docs/13-service-catalog.md. Serves R-GITOPS-02; ties into R-NET-*, R-STATE-*, R-TLS-*, R-DNS-*, R-OBS-*, R-UPD-*, R-IDP-*. Schema version: 1.10.0 (adds optional `availability` for the container kind, one member: `availability.replicas`. It is AVAILABILITY INTENT, not a scheduling primitive -- it names no Kubernetes object, no topology key and no budget. 1 (the default) renders a Deployment exactly as before, so every pre-existing app stays byte-identical; >1 means the service must survive the loss of a single node, and the renderer satisfies that with a StatefulSet whose longhorn volumes become per-replica volumeClaimTemplates (a longhorn PVC is ReadWriteOnce and cannot attach on two nodes, so a multi-replica Deployment is UNSCHEDULABLE, not merely suboptimal), REQUIRED podAntiAffinity on kubernetes.io/hostname (preferred would let every replica land on one node and deliver none of the intended tolerance while reporting healthy), podManagementPolicy Parallel, a PodDisruptionBudget of minAvailable 1, and an `up` SLI that follows the rendered kind (a Deployment-shaped rule against a StatefulSet absent()s forever and can never fire). Added for pihole, where LAN DNS -- a critical network service -- was one pod on one node: measured 2026-10-04, losing the node running it meant roughly 6-10 minutes with no LAN resolution (tolerationSeconds 300 plus node-NotReady detection plus a Longhorn RWO force-detach). Deliberately NOT usable until a service's state is reproducible from git, because a replica with a fresh volume otherwise comes up serving but unconfigured -- for pihole that prerequisite was done first (decisions/2026-10-04-pihole-declare-state.md). Capped at 5: a count above the node count can never schedule under the anti-affinity this implies. Mechanism documented in schemas/renderer-contract.md `### availability`). 1.9.0 (adds optional `auth.apiRoutes` -- a per-service list of anchored path regexes the forward-auth oauth2-proxy sidecar answers with 401 instead of a 302 to Keycloak, rendered as one repeatable `--api-route` per entry. The `auth` block stays `additionalProperties: false`; this is one named, documented key, not an opened door. Without it there was NO per-app override hook at all, so the only way to answer an app's XHRs with 401 was a renderer-wide constant -- and the path shape is a property of the app: jackett's is `/api/` (33 x 302 vs 2 x 401 measured 2026-09-30, 4 of 6 POSTs answered by the proxy and never reaching the app), radarr's is `/signalr/` (232 x 302 measured 2026-10-01, every one a POST from a left-open browser tab that is never re-prompted), and pihole serves no `/api/` at all. Each entry must be anchored at `^/` and continue with literal path characters, because a too-broad regex turns a plain page load into a 401 and the service looks permanently broken to a logged-out user. Enforced on every gate run by ci/l0.sh's schema stage over catalog/*.yaml, by catalog/render.py refusing to render an unanchored entry, and by conformance/tests/l0-static/oauth2-proxy-api-routes-per-app)). 1.8.0 (adds optional `hardware` - a host HARDWARE CAPABILITY declaration for the container kind, currently one member: `hardware.gpu: intel-quicksync`, meaning the workload needs the host iGPU render device for hardware video transcode. It is an ENUM OF INTENT, not a device path: the renderer satisfies it today with just two things -- a /dev/dri hostPath volume (`DirectoryOrCreate`) and a read-write /dev/dri volumeMount on the app container -- and a later move to the Intel GPU device plugin is then a render.py change with no catalog edit. It sets NO podSecurityContext.supplementalGroups: measured in-container on prod 2026-09-30, the pms-docker cont-init hook adds the app user to the device's group inside the container and `s6-setuidgid` then REPLACES the process group list from /etc/group, discarding anything Kubernetes supplied, so such an entry would be inert and misleading. Renders NOTHING when absent, so every existing app stays byte-identical. Emits no privileged securityContext (Kyverno restrict-host-namespaces would reject it and it is not needed), no nodeSelector (node placement is a separate concern with its own justification) and no resource requests). 1.7.0 (no field changes; a MAPPING change to `exposure`, which had never had an effect on DNS. `exposure: internal` now renders ExternalDNS's own controller annotation onto every HTTPRoute it emits, set to a value other than `dns-controller`, so external-dns (v0.21.0, source/gateway.go -> annotations.IsControllerMismatch) skips the route before resolving any hostname and the service is INCAPABLE of producing a public record. Both docs/09 R-DNS-03 and schemas/renderer-contract.mdLine truncated
   "type": "object",
   "additionalProperties": false,
   "required": ["name", "source"],
@@ -139,6 +139,21 @@
         "supplementalGroups": { "type": "array", "items": { "type": "integer" }, "description": "Additional GIDs added to the first process in each container." }
       }
     },
+    "availability": {
+      "type": "object",
+      "description": "Optional availability intent for the container kind: how many replicas of this workload must be running. INTENT ONLY -- it names no Kubernetes object and no scheduling primitive. How the platform satisfies it (workload kind, per-replica volumes, node spreading, disruption budget) is catalog/render.py's business, documented in schemas/renderer-contract.md `### availability`. Absent => replicas 1 and a Deployment, so every pre-existing app renders byte-identical. Ignored for kind=vm (a VM's availability is a different problem with different primitives).",
+      "additionalProperties": false,
+      "minProperties": 1,
+      "properties": {
+        "replicas": {
+          "type": "integer",
+          "description": "How many replicas must be running. 1 (default) renders a Deployment exactly as before. >1 declares that the service must survive the loss of a single node; the renderer then emits a StatefulSet with per-replica volumeClaimTemplates, required per-node anti-affinity, podManagementPolicy Parallel and a PodDisruptionBudget. Only declare >1 for a service whose on-disk state is reproducible from git -- a replica with a fresh volume comes up serving whatever it can bootstrap itself, and nothing else.",
+          "minimum": 1,
+          "maximum": 5,
+          "default": 1
+        }
+      }
+    },
     "hardware": {
       "type": "object",
       "description": "Optional host HARDWARE CAPABILITY the workload needs, for the container kind (docs/13). This field declares INTENT (`what device class this service needs`), never MECHANISM (`which host path to bind-mount`, `which extended resource to request`). That separation is the whole point of the enum: the platform currently satisfies `intel-quicksync` with a /dev/dri hostPath volume and a matching mount on the app container, but a later migration to the Intel GPU device plugin (`gpu.intel.com/i915` resource requests, no hostPath) must be a catalog/render.py change and NOTHING else - no ServiceDefinition may need editing, and no reviewer may have to re-derive per-service device wiring. Do NOT 'simplify' this into a raw device path, a hostPath, or a resource request; that would push a platform implementation detail into the operator-facing contract and make the migration a catalog-wide edit. Absent => no device wiring at all (existing apps render byte-identical). Ignored for kind=vm (a VM gets devices through KubeVirt's own domain.devices).",