Workstreams A, B, G, H, I of the DNS reliability plan (code-q2e).
Follow-ups for C, D, E, F filed as code-2k6, code-k0d, code-o6j, code-dw8.
**Technitium (WS A)**
- Primary deployment: add Kyverno lifecycle ignore_changes on dns_config
(secondary/tertiary already had it) — eliminates per-apply ndots drift.
- All 3 instances: raise memory request+limit from 512Mi to 1Gi (primary
was restarting near the ceiling; CPU limits stay off per cluster policy).
- zone-sync CronJob: parse API responses, push status/failures/last-run and
per-instance zone_count gauges to Pushgateway, fail the job on any
create error (was silently passing).
**CoreDNS (WS B)**
- Corefile: add policy sequential + health_check 5s + max_fails 2 on root
forward, health_check on viktorbarzin.lan forward, serve_stale
3600s/86400s on both cache blocks — pfSense flap no longer takes the
cluster down; upstream outage keeps cached names resolving for 24h.
- Scale deploy/coredns to 3 replicas with required pod anti-affinity on
hostname via null_resource (hashicorp/kubernetes v3 dropped the _patch
resources); readiness gate asserts state post-apply.
- PDB coredns with minAvailable=2.
**Observability (WS G)**
- Fix DNSQuerySpike — rewrite to compare against
avg_over_time(dns_anomaly_total_queries[1h] offset 15m); previous
dns_anomaly_avg_queries was computed from a per-pod /tmp file so always
equalled the current value (alert could never fire).
- New: DNSQueryRateDropped, TechnitiumZoneSyncFailed,
TechnitiumZoneSyncStale, TechnitiumZoneCountMismatch,
CoreDNSForwardFailureRate.
**Post-apply readiness gate (WS H)**
- null_resource.technitium_readiness_gate runs at end of apply:
kubectl rollout status on all 3 deployments (180s), per-pod
/api/stats/get probe, zone-count parity across the 3 instances.
Fails the apply on any check fail. Override: -var skip_readiness=true.
**Docs (WS I)**
- docs/architecture/dns.md: CoreDNS Corefile hardening, new alerts table,
zone-sync metrics reference, why DNSQuerySpike was broken.
- docs/runbooks/technitium-apply.md (new): what the gate checks, failure
modes, emergency override.
Out of scope for this commit (see beads follow-ups):
- WS C: NodeLocal DNSCache (code-2k6)
- WS D: pfSense Unbound replaces dnsmasq (code-k0d)
- WS E: Kea multi-IP DHCP + TSIG (code-o6j)
- WS F: static-client DNS fixes (code-dw8)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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