home-network-k3s-impl/docs/plans/l2-l3-conformance-ci-wiring.md

# L2/L3 conformance CI wiring — implementation plan

**Status:** PLAN — deferred, awaiting operator decision on the trigger-credential model. No
cluster changes made.
**Author:** WS-GITOSS agent, 2026-08-31 (Hand-off 2).
**Scope:** wire the L2 (behavioural) + L3 (fault-injection) conformance layers into the LIVE
Gitea Actions merge gate, running them as an **in-cluster Chainsaw Job** so CI holds **no broad
kubeconfig** (docs/14 "Where each layer runs", ADR-0011, R-SEC-02).

> This companions the landed Hand-off 1 (commit `27bc024`: `make -C ci gate` parity + the
> comment-only R-ID scan fix). The `conformance` job in `.gitea/workflows/gate.yml` is still an
> honest `if: false` placeholder — this plan is what turns it on **safely**.

---

## 1. Why this is a written plan, not a landed change

The intended seam is real and mostly scaffolded, but finishing it autonomously would mean
handing a shared, **live** cluster a new privileged identity reachable from CI, plus building
several missing functional pieces. The hand-off's rule is explicit: *if wiring real cluster
access from CI is too risky/ambiguous to finish autonomously, STOP and write a concrete plan —
do NOT hand CI a broad kubeconfig.* The blocker is a genuine **privilege-escalation** design
question (§4), not just plumbing, and the cluster is being changed concurrently by sibling
agents. So the credential model must be decided by the operator before anything is applied.

---

## 2. Current state (what exists today)

| Piece | File | State |
|---|---|---|
| Live gate workflow | `.gitea/workflows/gate.yml` | LIVE. `gate` job runs `make -C ci gate`. `conformance` job is `if: false` placeholder. |
| Dormant full blueprint | `.gitea/workflows/merge-gate.yaml` | Shows the intended shape: `conformance` job `if: ${{ vars.CLUSTER_AVAILABLE == 'true' }}`, `secrets.CONFORMANCE_TRIGGER_KUBECONFIG`, `make -C ci conformance`, then a `merge-gate` decision job (`scripts/decide.sh`). Manual-only (`workflow_dispatch`). |
| CI conformance stage | `ci/conformance.sh` | SKIPS (exit 3) unless `CLUSTER_AVAILABLE=true`. When "on", it currently runs `conformance/run.sh --layer l2,l3` **locally in the CI job** and collects `_artifacts/`. Its own header carries `TODO(Phase 1): drive the in-cluster Chainsaw Job under the narrow CONFORMANCE_TRIGGER_KUBECONFIG` — i.e. the trigger path is **not implemented**. |
| Conformance runner | `conformance/run.sh` + `conformance/lib/`, `conformance/tests/` | Works locally/in-cluster. `--layer l2,l3 [--requirements ...]`, writes `_artifacts/report.junit.xml` + `coverage/`. Needs bash + python3 + chainsaw (+ kubectl for `conf_cluster_reachable`). |
| In-cluster Job skeleton | `conformance/incluster/chainsaw-job.yaml` | Skeleton: `generateName: conformance-run-`, ns `conformance`, `serviceAccountName: conformance-runner`, image `ghcr.io/kyverno/chainsaw:v0.2.12`, `command: ["./run.sh"]`, args default `--layer all --strict-coverage`. **`workspace` is an empty `emptyDir` with no init-container to populate it**, and `results` is an `emptyDir`. |
| Scoped runner RBAC | `conformance/incluster/rbac.yaml` | ns `conformance` + SA `conformance-runner` + a **privileged** ClusterRole (namespaces create/delete/patch, pods+pods/exec, jobs create/delete, **nodes get/list/patch** for R-STATE-02 cordon, pods/log). Least-privilege, per-test-justified. **Not reconciled by Flux** (no kustomization references `conformance/incluster/`). |
| Runner deployment | `apps/wave-1/gitea-actions.yaml` | act_runner + DinD (Docker executor). **`automountServiceAccountToken: false`** — the runner and its job containers hold NO SA token. Broad egress allowed (`- {}`), so it can *reach* the kube-API VIP `192.168.1.49:6443`, but has no credential. |
| Secrets encryption | `.sops.yaml` (repo root) | age recipient `age175l8m…mfzg`; encrypts `data`/`stringData` of `*.sops.yaml` under `platform|apps|catalog/**` and `secrets/**`. Private key is the in-cluster `sops-age` Secret Flux uses. |

**Cluster reality:** the "Phase 0 / no cluster" language in these files is stale — the dev cluster
is LIVE (Phase 6). So `CLUSTER_AVAILABLE` is the only remaining gate, exactly as the blueprint says.

---

## 3. Gaps to close (functional)

1. **Runner image.** `ghcr.io/kyverno/chainsaw` is a minimal image; `run.sh` needs **bash +
   python3 + chainsaw + kubectl**, and the repo-clone init needs **git**. The Job cannot run
   `./run.sh` on the stock chainsaw image. → Build a pinned `conformance-runner` image (chainsaw
   `v0.2.12` + kubectl `v1.36.4` + git + python3 + bash), push to the Gitea container registry,
   pin its digest in `conformance/versions.env` (`CONFORMANCE_RUNNER_IMAGE`). Keep
   `CHAINSAW_VERSION` as the single source of truth the image is built from.
2. **Repo at the commit-under-test.** The Job must run the suite at the PR head SHA. → Add an
   **init-container** (`git clone --depth 1` of the impl repo, then `git checkout <SHA>`) writing
   into the shared `workspace` volume, using a **read-only** Gitea deploy token. SHA + the touched
   `--requirements` are injected by the CI trigger step as Job env/args.
3. **Results collection without giving CI exec/cp.** The Job writes `_artifacts/` to the `results`
   volume; CI holds only trigger/read rights (§4). → Job's last step prints a delimited
   base64 tar of `_artifacts/` to stdout (`=== ARTIFACTS-TGZ-BASE64 ===`…); CI decodes it from
   `kubectl logs`. No `pods/exec`, no `kubectl cp`, no results PVC exposure required. (A results
   PVC + a read-only sidecar is the durable alternative if log size becomes a problem.)
4. **`ci/conformance.sh` rewrite.** Replace the local `run.sh` call with: render the Job manifest
   (inject image digest, SHA, `--requirements <touched>`), `kubectl --kubeconfig=$CONFORMANCE_TRIGGER_KUBECONFIG
   -n conformance create -f -`, `kubectl wait --for=condition=complete/failed`, stream logs,
   decode artifacts into `results/junit` + `reports/coverage`, map Job success→0 / failure→1 /
   no-cred→3 (skip). Keep the touched-subset selection it already computes.
5. **Flux wiring.** Reconcile `conformance/incluster/` (ns + `conformance-runner` SA/RBAC + the
   new trigger SA/Role + the admission policy of §4) via a **non-gating** Kustomization
   (`wait:false`, `dependsOn: platform-config`), mirroring `apps-vms` — a conformance identity
   must never gate the app tier.
6. **Gitea provisioning (operator, out-of-GitOps).** Set repo/org `vars.CLUSTER_AVAILABLE=true`
   and `secrets.CONFORMANCE_TRIGGER_KUBECONFIG` via the Gitea API
   (`PUT /repos/{owner}/{repo}/actions/{variables,secrets}/{name}`). The kubeconfig embeds the
   trigger SA's token only. SOPS-seal the SA token in-repo (`secrets/conformance-trigger.sops.yaml`)
   for reproducibility/rotation; the Gitea secret is derived from it.

---

## 4. The security crux — trigger credential must NOT grant `conformance-runner`'s power

**Problem.** Kubernetes places no `use` check on a Pod/Job's `serviceAccountName` at creation.
So **any principal that can `create jobs` in namespace `conformance` can create a Job with
`serviceAccountName: conformance-runner` and an arbitrary `command`** — i.e. run arbitrary code
with the privileged runner SA (nodes/patch, pods/exec, jobs, namespaces/patch). A CI-held token
with plain `create jobs` therefore *is* the privileged identity. That breaks R-SEC-02 ("CI holds
no broad cluster access") even though the token's RBAC "looks" narrow.

**Recommended model — narrow trigger SA + an admission constraint (uses the existing Kyverno L0
stack):**

- SA `conformance-trigger` (ns `conformance`), Role: `create` on `jobs`; `get,list,watch` on
  `jobs`; `get` on `pods` and `pods/log`. Nothing else. Bound only in the `conformance` ns.
- A **Kyverno ClusterPolicy (validate, enforce, fail-closed)** that, *for Jobs created by
  `system:serviceaccount:conformance:conformance-trigger`*, ADMITS only Jobs that match the
  committed shape: image == the pinned `CONFORMANCE_RUNNER_IMAGE` digest,
  `serviceAccountName == conformance-runner`, `command == ["./run.sh"]`, `args` matching
  `^--(layer|requirements|strict-coverage)`, `securityContext` non-root/no-privilege/no host
  namespaces, and no extra volumes beyond `workspace`/`results`. Any other Job from that SA is
  DENIED. This is the real security boundary: it bounds CI to "run exactly the committed
  conformance suite, nothing else." (Equivalent: a k8s ValidatingAdmissionPolicy bound to that SA.)
- The `chainsaw-conf-*` per-test namespaces the runner creates are already flagged in
  `rbac.yaml` as needing exclusion from any cluster-wide disallow-privileged/host-namespaces
  policy for R-NET-06 — carry that exception through, documented and audited.

**Alternative model — GitOps-native, zero CI cluster credential (more work, strongest):** CI does
not reach the cluster at all. A `ConformanceRun` marker (a CR or a commit to a watched path) is
reconciled by an in-cluster controller/Flux that creates the Job from the in-repo template; the
Job publishes results back as a Gitea commit-status / a fetchable artifact that CI polls. Removes
the trigger credential entirely, at the cost of a controller and a trigger/ordering mechanism that
must complete before the merge decision. Recommended only if even the constrained trigger SA of
the primary model is deemed unacceptable.

**Do NOT:** give CI a `cluster-admin`/broad kubeconfig; give the trigger SA unconstrained
`create jobs`; mount an SA token into the act_runner pod; or reuse `conformance-runner` as the
trigger identity.

---

## 5. Concrete step sequence

Land these as separate reviewable PRs, gate-green at each step. Steps 1–5 are in-repo/GitOps and
safe to land incrementally *without* turning L2/L3 on; only step 7 (the operator setting the Gitea
var) actually enables it.

1. **Runner image.** `conformance/incluster/Containerfile` (chainsaw+kubectl+git+python3+bash);
   build+push to the Gitea registry; pin `CONFORMANCE_RUNNER_IMAGE=<registry>/conformance-runner@sha256:…`
   in `conformance/versions.env`. Add a note tying it to `CHAINSAW_VERSION`.
2. **Job manifest.** Rewrite `chainsaw-job.yaml`: swap to `CONFORMANCE_RUNNER_IMAGE`; add the
   git-clone init-container (SHA + repo URL + read token env); parametrise `args` (CI injects
   `--layer l2,l3 --requirements <touched>`); keep `restartPolicy: Never`, `backoffLimit: 0`,
   non-root/seccomp/readonly-rootfs; add sane CPU/mem requests+limits (heavy L3 etcd load —
   see `run.sh` HEAVY set + `config/chainsaw-config.yaml`).
3. **Trigger SA/RBAC + admission policy.** Add `conformance-trigger` SA + Role/RoleBinding to
   `rbac.yaml`; add the Kyverno ClusterPolicy (new file under `platform/kyverno/` or
   `conformance/incluster/`) constraining that SA's Jobs (§4). Add an L0 Kyverno test fixture for
   the policy (admit the good Job, deny a tampered one) so `make -C ci l0` covers it.
4. **Flux Kustomization.** New `clusters/<cluster>/conformance.yaml` (or an `apps-conformance`
   entry) — `wait:false`, `dependsOn: platform-config`, `prune:true`, pointing at
   `conformance/incluster/`. No `postBuild.substituteFrom` unless needed. Verify it reconciles
   Ready with the SA/RBAC/policy present and NO Job running (Jobs are created only on trigger).
5. **`ci/conformance.sh` rewrite.** Implement the trigger→wait→collect→map flow of §3.4 behind
   `CONFORMANCE_TRIGGER_KUBECONFIG`; keep exit 3 when the cred is absent (honest skip). Update
   `ci/README.md`. `make -C ci gate` still SKIPS L2/L3 locally (no cred) — unchanged for humans.
6. **Workflow.** Replace the `if: false` placeholder in `gate.yml`'s `conformance` job with the
   blueprint shape: `if: ${{ vars.CLUSTER_AVAILABLE == 'true' }}`, `needs: [gate]`, install the
   `conformance` toolchain, `env: CONFORMANCE_TRIGGER_KUBECONFIG: ${{ secrets.CONFORMANCE_TRIGGER_KUBECONFIG }}`,
   `run: make -C ci conformance`. Decide: either keep the single-`gate` model (aggregate `gate.sh`
   already SKIPS conformance and reports UNVERIFIED) and add conformance as a **second required
   check**, or adopt the blueprint's separate `merge-gate` decision job (`scripts/decide.sh`).
   Keep the job honest: skipped when the var is off, never faked green (HARD RULE 4). Add the
   conformance check to branch protection only after step 7 proves it green.
7. **Enable (operator).** Provision the SOPS-sealed trigger SA token; set the Gitea
   `secrets.CONFORMANCE_TRIGGER_KUBECONFIG` and `vars.CLUSTER_AVAILABLE=true`. First run on a
   throwaway PR; confirm the Job is created, runs the touched subset, results are collected, and
   the gate blocks on a real L2/L3 failure and passes on green. Then make it required.

---

## 6. Validation & rollback

- **Dry-run the admission policy** before granting the trigger SA: `kubectl auth can-i` matrix for
  `conformance-trigger`; attempt a *tampered* Job (different command) as that SA and confirm
  Kyverno DENIES it; attempt the committed Job and confirm ADMIT.
- **Fail-closed check:** temporarily break an L3 test, confirm the Job fails and the gate BLOCKS
  (mirrors Hand-off 1's proof that `gate.sh` exit 1 fails the job).
- **Rollback:** unset `vars.CLUSTER_AVAILABLE` (instant SKIP, gate reverts to L0/L1-only) and/or
  suspend the Flux Kustomization; delete the trigger SA token from Gitea secrets. No app-tier
  impact (conformance is a non-gating tier).

---

## 7. Open decisions for the operator

1. **Trigger model:** constrained trigger SA + Kyverno admission policy (§4 primary) vs.
   GitOps-native zero-credential (§4 alternative). This plan recommends the primary.
2. **Runner image host:** Gitea container registry (in-network, matches the Flux source loop) vs.
   ghcr.io. Recommend Gitea registry, digest-pinned.
3. **Gate topology:** conformance as a second required check on the single-job `gate.yml` vs.
   restoring the blueprint's multi-job `merge-gate.yaml` with the `decide.sh` decision job.
4. **Results transport:** base64-tar-over-logs (simple, no extra rights) vs. a results PVC +
   read-only sidecar (durable). Recommend logs first; revisit if artifacts grow.
5. **Which requirements go live first:** the R-NET/R-TLS/R-DNS/R-STATE tests already green against
   the live cluster (per DECISIONS-LOG) are the natural first `--requirements` subset to certify
   through the wired path before widening.