INCIDENT FIX. Prod's external-dns DELETED EVERY ONE OF DEV'S PUBLIC DNS RECORDS. Both
clusters ran policy: sync against the SAME Cloudflare zone with the SAME implicit
txtOwnerId (`default`), so prod believed it owned dev's records, found no matching sources,
and removed them plus their TXT registry entries. Dev recovered ~30s after prod was scaled
to 0; verified restored against Cloudflare directly (my first check went through a pfSense
override and falsely showed healthy — local resolvers are not evidence about public DNS).
THE MISS WAS MINE, and it was a failure of imagination in how I briefed every agent. I put
"never touch dev" in brief after brief and enforced it — separate kubeconfigs, verified
--limit, sha-checked dev's kubeconfig before and after. Every one of those guards held. NONE
of them covered SHARED EXTERNAL RESOURCES. Prod reconciling its OWN correctly-authored
manifests reached across a third party and destroyed dev's state. Cluster-to-cluster
isolation was verified; the dependency that mattered was cluster-to-Cloudflare.
Operator's architecture: dev -> *.dev.home.keithjackson.dev, prod ->
*.prod.home.keithjackson.dev, apex CNAME <svc>.home -> <svc>.prod.home.
PHASE 1 ONLY (this commit): prod moves to its own subdomain. DEV IS NOT MIGRATED and its
effective hostname stays home.keithjackson.dev, so dev renders byte-identically and nothing
live moves. That alone ends the collision and unblocks prod. Phase 2 (dev -> dev.home. +
apex CNAMEs) is deferred to when the operator is present: it relocates Keycloak's issuer and
12 clients' redirect URIs, forces a rolling k3s restart and kubectl SSO re-issue for every
user, and moves gitea.home. — which is BOTH the GitOps source and the current push target.
BASE_DOMAIN WAS A DEAD KNOB — it existed in cluster-vars but the status report flagged it as
referenced by nothing, because hostnames were hardcoded throughout. Now real: 141 refs.
Searched the AUTHORITATIVE reconciled set by resolving each Flux spec.path transitively via
conformance/lib/status.py — the same resolver the L0 gate uses, so "what Flux reconciles"
has one definition. 185 occurrences across 47 files in 154 reconciled files. Tokenized:
Gateway listeners, the wildcard Certificate, coredns-custom, external-dns, Keycloak
instance/realm (26 redirect URIs), oauth2-proxy, Grafana OIDC, all HTTPRoutes, Homepage's 15
links, 30 runbook_urls, unifi cloud-init, render.py's ZONE constant (which drove
--oidc-issuer-url/--cookie-domain/--whitelist-domain on every forward-auth sidecar) and 11
catalog/ ServiceDefinitions re-rendered canonically. Left alone: 43 comment/prose
occurrences and non-reconciled paths.
TWO THAT CANNOT BE TOKENIZED, flagged not forced:
- headlamp's OIDC URLs live inside a SOPS-encrypted Secret; re-encrypting rewrites the MAC
over every value and the OFFLINE harness cannot verify it (kustomize does not decrypt),
so an error would break live-dev SSO with no pre-flight proof. Prod needs its own copy
anyway — client secrets are realm-scoped.
- kube-apiserver --oidc-issuer-url is a k3s SERVER FLAG, not a manifest, so Flux can never
reach it. Done on the inventory seam instead (k3s_base_domain -> k3s_oidc_issuer_url,
overridden in group_vars/k3s_prod). Verified per host: dev keeps the default, prod gets
prod.home.
EXTERNAL-DNS OWNER, the actual incident cause: txtOwnerId is now explicit per environment —
dev renders exactly `default` (the chart default it was already using, so its existing
records stay recognised) and prod gets `prod`. The BASE default is a NON-COLLIDING SENTINEL,
deliberately not `default`, so a future environment that forgets the knob owns nothing and
can delete nothing rather than silently inheriting dev's identity.
I OVERRODE ONE AGENT DECISION against our own prior finding: it narrowed prod's
domainFilters to prod.home.keithjackson.dev as defence in depth. FINDING F-DNS1
(DECISIONS-LOG 2026-08-17) already proved a subdomain filter DROPS THE PARENT ZONE —
ExternalDNS generates the record then skips it with "no hosted zone matching record DNS
Name". Prod would have published NOTHING. Set to the ZONE (keithjackson.dev) like dev.
Isolation comes from the subdomain split plus txtOwnerId, which is what the incident
actually needed and what a domain filter cannot provide.
DEV PROVEN UNCHANGED: 11 of 12 substituting paths byte-identical; the 12th differs by
exactly one line, `+ txtOwnerId: default` — the value dev was already using implicitly.
POSITIVE CONTROLS confirm the harness is not blind: perturbing BASE_DOMAIN moves 10 of 12
hashes (the 2 that don't provably contain no hostname), perturbing the owner id moves
exactly 1. Prod's rendered output has ZERO home.keithjackson.dev references outside prod.,
and its cert renders *.prod.home.keithjackson.dev — no overlap with dev's.
L0 substitution assertions 106 -> 254; BASE_DOMAIN is no longer flagged dead. Gate PASS.
PROD REMAINS SUSPENDED (platform + 10 downstream tiers) pending review; nothing applied.
Serves: R-ENV-02, R-DNS-01, R-DNS-02, R-DNS-03, R-TLS-01.
Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Adds NodeCPUPressureHigh (CPU PSI 'some' > 15% for 15m) and NodeCPULoadHigh (load5/core > 1 for 15m)
to platform-health.nodes, plus a 'Nodes — CPU / Memory Pressure' Grafana dashboard (PSI + load-per-core
+ utilization). These surface the bursty CPU contention that averaged CPU%/kubectl top hides — the
signal behind 'spikes cause blips of delay'. Makes the 6->8 vCPU resize measurable.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
Add platform-health.automated-updates PrometheusRule group carried by platform-config:
ImageUpdateAutomationFailing (write-back broken -> advances silently stop),
ImagePolicyStalled (registry/range can't resolve a stable tag), and UpdateHealthGateFailed
(a bad update health-gated and auto-rolling-back via HelmRelease remediation). Routes to
Alertmanager email so a bad update is visible.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
gluetun retirement removes the gluetun_vpn_up gauge and the in-cluster gateway pod. Point
VPNTunnelDown at absent(node_network_receive_bytes_total{device=tun0}) — tun0 exists iff the
host OpenVPN tunnel is up (node_network_up unreliable: tun0 operstate=unknown). This also
fires if the gateway node/node-exporter is down (series goes stale). Remove the pod-readiness
EgressGatewayUnhealthy alert — there is no gateway pod under ADR-0015.
Co-Authored-By: Claude Opus 4.8 <[email protected]>
jakman85andClaude Opus 5