## Why
6 hosts (ausyd1nxvm2069-2073, 2098) ended up with a reverse PTR in bind-authoritative but **no forward A record**, and the `unkin.net` service records (git/grafana/auth/fafflix, all published by the halb host 2069) never landed at all.
VictoriaLogs (`dns-update-apply` on 2069 & 2070) shows the cause:
```
dns-update: nsupdate to 198.18.200.9 failed
invalid owner name: empty label
syntax error
```
`profiles::dns::record` publishes some records whose name is already fully-qualified (trailing dot) — e.g. `au-syd1-pve.main.unkin.net.`, `cobbler.main.unkin.net.`, `dashboard.ceph.unkin.net.`, and the halb CNAMEs. The `dns-update` script `fqdn()` unconditionally appended the zone, producing `…net..main.unkin.net.` — the `..` is an empty label, which nsupdate rejects, failing the entire per-zone `send`. The reverse-PTR send is sorted first and its name is always relative, so it still applied — hence "PTR but no A".
## Change
`fqdn()` now handles three cases:
- `@`/empty → zone apex (unchanged)
- name ending in `.` → already FQDN, used verbatim (**the fix**)
- otherwise → relative, append `.zone.` (unchanged)
Verified against all record shapes (relative host, apex, FQDN CNAME, reverse label) — no more `..`.
## After merge
Once puppet re-runs on the affected hosts their `main.unkin.net`/`unkin.net` updates succeed, filling in the missing A records and the `unkin.net` service zone. Pairs with argocd-apps#260 (adds the `ceph.unkin.net` zone so `dashboard.ceph.unkin.net` does not then hit NOTZONE).
Reviewed-on: #481
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
Replaces the exported-resources → puppet DNS master zone-file flow with per-host RFC2136 dynamic updates against the k8s **bind-authoritative** write endpoint (198.18.200.9). The master no longer manages zone files.
## Design
Each node assembles its DNS records into a local concat file; a systemd `.path` unit watches it and runs `dns-update` (nsupdate) on change — exactly the watch-a-file model requested.
## Changes
- **profiles::dns::updater** (new): concat records file + TSIG key file + `dns-update` script + `dns-update.service` (oneshot) + `dns-update.path` (watcher). The script sends only the delta since last run and deletes removed records, grouped per zone.
- **profiles::dns::record**: writes a local concat fragment (`zone|name|type|ttl|value`) instead of exporting `@@concat::fragment` to the master.
- **profiles::dns::base**: includes `profiles::dns::updater` (all nodes).
- **hiera**: `profiles::dns::updater` server/key_name/algorithm in common.yaml.
## Inert until keyed
The updater does nothing until `profiles::dns::updater::key_secret` (TSIG) is set in eyaml — records are assembled but not applied, so nodes are safe before the key exists.
## Prerequisites (k8s side, separate)
1. The `bind-authoritative` zones must set `dynamicUpdate: true` + an `updateKeyRef` (a client-update BindTSIGKey) so they accept these updates.
2. The TSIG key must be shared: the operator-generated key value goes into eyaml here (or the planned Vault-sync feature bridges it).
## Validated
puppet parser/epp validate, puppet-lint, and a functional test of the generated per-zone nsupdate message (replace + delete-removed).
Reviewed-on: #475
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>
unkinben