Files
home-network-k3s-impl/conformance/tests/l2-behavioral/dns-internal-resolution/chainsaw-test.yaml
T
jakman85andClaude Opus 5 6a8953e288 feat(prod): observability for the two failure modes that went unseen, plus OIDC self-healing
Minimal prod delivery, authored directly on main (= prod's live revision d1a6628)
rather than by merging work/prod-standup-campaign. That branch carries the DNS apex
inversion, which would have set prod's BASE_DOMAIN to home.keithjackson.dev; prod
runs external-dns with policy: sync and txtOwnerId: prod, so it would have begun
rewriting apex records dev owns while the non-k3s prod still serves 443 there.
Operator sequencing is "dev migrates first". Nothing under clusters/ is touched
here at all, which is what makes this safe to land now.

Also deliberately EXCLUDED, because prod's live cluster-vars has no CNPG_BACKUP_PATH
key and StrictPostBuildSubstitutions would fail the whole tier: the R2 rework of
platform/velero/ and the CNPG destinationPath changes. Those land as
feat/r2-backup-prod together with the endpoint and bucket knobs.

WHAT THIS FIXES

1. Nothing was watching CNPG. All three prod databases have run since bootstrap with
   ContinuousArchiving=False and firstRecoverabilityPoint=null, and no alert existed
   anywhere. Because archive_mode=on and the archive command fails, Postgres refuses
   to recycle WAL: keycloak-db holds every segment ever written (257 MiB on a 5 GiB
   volume, ~6.8 MiB/h) — roughly 29 days to a disk-full PANIC on the cluster's SSO
   database. Found by hand, 38h late. CNPGWALArchiveBacklog would have fired within
   the hour, and evaluates to 3 firing series on prod today.
   Rules key on cnpg_collector_* rather than cnpg_pg_stat_archiver_*, because
   nextcloud-db's exporter cannot log in to its own database (permission denied for
   database "nextcloud", both clusters) so the pg_stat_archiver family does not exist
   for it — the obvious metric would have been blind to one database in three.

2. No PVC outside namespace=monitoring had any fill alert. New rules are partitioned
   by namespace so they cannot double-fire with MonitoringVolumeFillingUp, pinned to
   job="kubelet" (the apiserver copy of the same series reports namespace=default),
   and guarded by inodes > 0 — block-mode PVCs such as unifi-rootdisk report
   available=0 forever and would otherwise have fired critical permanently.

3. VPNTunnelDown could never clear on a cluster with no gateway node; it has been
   firing critical on prod since 2026-09-05. Now guarded so prod self-arms the moment
   a node carries the egress-gateway label, with dev's behaviour unchanged today.

4. The Keycloak realm import fails OPEN: an unresolved placeholder is stored
   LITERALLY and the import still reports success, then sits at Done=True and never
   re-runs. On 2026-09-06 all 12 prod OIDC clients held the literal
   $(env:..._CLIENT_SECRET) string and every SSO login failed, while every signal was
   green. The CronJob is the level-triggered correction; two alerts make its silence
   observable. Repaired live already — this stops it recurring.

Also: the R-NET-04 conformance scan descended into nested agent worktrees under
.claude/, counting 4 egress policies where 1 is authored.

Co-Authored-By: Claude Opus 5 <[email protected]>
2026-09-07 00:59:22 -05:00

115 lines
6.0 KiB
YAML

# =============================================================================
# L2 BEHAVIORAL — split-horizon INTERNAL resolution (R-DNS-01 / R-DNS-03) [RUNNABLE]
# Catalog: docs/14 "DNS/exposure (R-DNS-*)"
# Spec: docs/09 "Split-horizon resolution (R-DNS-03)" — internal clients resolve
# <svc>.${BASE_DOMAIN} to the INTERNAL Gateway VIP, not the public hairpin.
# Impl: platform/coredns/coredns-custom.yaml (k3s CoreDNS `import *.server`; template plugin
# answers the whole ${BASE_DOMAIN} zone with ${GATEWAY_VIP}).
#
# ENVIRONMENT-AGNOSTIC (R-ENV-02): this test asks the CLUSTER IT IS POINTED AT for its own
# ${BASE_DOMAIN} and ${GATEWAY_VIP} — the same flux-system/cluster-vars ConfigMap Flux
# substitutes from — via test-level chainsaw bindings (see `spec.bindings`). Nothing here is
# per-environment and no flag is passed at run time, so the suite cannot be run against the
# wrong expectation: dev asserts dev's zone/VIP, prod asserts prod's.
#
# GIVEN the split-horizon coredns-custom ConfigMap is reconciled into k3s CoreDNS,
# WHEN an in-cluster pod resolves a platform hostname over its PUBLIC name
# (keycloak.${BASE_DOMAIN}) using the default cluster resolver (CoreDNS 10.43.0.10),
# THEN the answer is EXACTLY that cluster's ${GATEWAY_VIP} (the address coredns-custom is
# templated with, and the `shared` Gateway's own status address) — NOT a public/off-cluster
# IP. This is what lets pod->public-hostname traffic hairpin through the
# Gateway with the correct SNI (*.${BASE_DOMAIN}) so the wildcard cert validates
# (R-DNS-01 "services reachable at <svc>.${BASE_DOMAIN}"; R-DNS-03 split-horizon).
#
# Complements dns-exposure (R-DNS-02, the EXTERNAL/public-record side). Together they cover the
# split-horizon pair: external answer = public record (R-DNS-02); internal answer = Gateway VIP
# (R-DNS-01/03).
#
# CLEANUP: chainsaw deletes the per-test namespace (Job included) at teardown. Read-only otherwise.
# chainsaw v0.2.12: Job + status assert; no test-level finally.
# =============================================================================
apiVersion: chainsaw.kyverno.io/v1alpha1
kind: Test
metadata:
name: dns-internal-resolution
labels:
conformance.home.k3s/R-DNS-01: "true"
conformance.home.k3s/R-DNS-03: "true"
annotations:
conformance.home.k3s/requirements: "R-DNS-01,R-DNS-03"
conformance.home.k3s/layer: "L2"
conformance.home.k3s/safety-critical: "false"
conformance.home.k3s/executable: "true"
conformance.home.k3s/intent: >-
An in-cluster pod resolving keycloak.${BASE_DOMAIN} via cluster DNS gets that cluster's
internal Gateway VIP, not the public hairpin — split-horizon in-cluster resolution.
spec:
timeouts:
apply: 60s
assert: 2m
exec: 2m
# -- R-ENV-02: the environment's identity is READ FROM THE CLUSTER UNDER TEST, never authored
# here. flux-system/cluster-vars is the ConfigMap Flux itself substitutes from
# (clusters/base/cluster-vars.yaml + the dev/prod overlay patch), so these bindings are the
# same source of truth the platform is rendered from. Test-level => in scope for every step
# (unlike step `outputs`, which are step-scoped).
bindings:
- name: baseDomain
value: (x_k8s_get($client, 'v1', 'ConfigMap', 'flux-system', 'cluster-vars').data.BASE_DOMAIN)
- name: gatewayVip
value: (x_k8s_get($client, 'v1', 'ConfigMap', 'flux-system', 'cluster-vars').data.GATEWAY_VIP)
steps:
- name: then-cluster-dns-answers-with-the-internal-gateway-vip
try:
- apply:
resource:
apiVersion: batch/v1
kind: Job
metadata:
name: dns-internal-probe
spec:
backoffLimit: 2
activeDeadlineSeconds: 100
template:
spec:
restartPolicy: Never
containers:
- name: probe
image: busybox:1.36.1
# The cluster's OWN identity, resolved from flux-system/cluster-vars by the
# test-level bindings — never a literal (R-ENV-02).
env:
- name: BASE_DOMAIN
value: ($baseDomain)
- name: GATEWAY_VIP
value: ($gatewayVip)
command:
- sh
- -c
- |
set -u
host="keycloak.${BASE_DOMAIN}"
# Resolve via the DEFAULT cluster resolver (CoreDNS, /etc/resolv.conf ->
# 10.43.0.10). Split-horizon must answer with THIS cluster's Gateway VIP
# (the address coredns-custom is templated with), proving pods hairpin
# through the Gateway. Exact match on ${GATEWAY_VIP}: stricter than the
# old hardcoded 192.168.1.53-.60 range AND correct in both environments.
out="$(nslookup "$host" 2>/dev/null)"
echo "$out"
ip="$(echo "$out" | awk '/^Address: /{print $2}' | grep -Fx "${GATEWAY_VIP}" | head -1)"
if [ -n "$ip" ]; then
echo "INTERNAL_RESOLUTION_OK $host -> $ip (in-cluster Gateway VIP)"
exit 0
fi
echo "FAIL: $host did not resolve to this cluster's Gateway VIP (${GATEWAY_VIP});"
echo " split-horizon coredns-custom not in effect (got a public/off-cluster answer)."
exit 1
- assert:
resource:
apiVersion: batch/v1
kind: Job
metadata:
name: dns-internal-probe
status:
succeeded: 1