Files
automations/deployments/knot-dns
57_WolveandClaude Opus 5 0c151ce79b feat(knot-dns): add the missing host-level installer
The deployment shipped its payload but not the thing that installs it.
54a5c09 added README, knot.conf, knsctl, zone.tmpl, secrets.conf.example,
the aliases and the MOTD -- but no deploy.sh, no cloud-init.yml, and no
entry in automations.sh's DEPLOYMENTS. `git log --all` confirms deploy.sh
was never committed and it is not gitignored, yet README.md:96 and :100
tell the operator to run it. So the documented install path did not exist.

Alpine only, native, matching the README: Knot binds :53 directly, needs
real client addresses for RRL and cookies, and keeps its DNSSEC key store on
the host filesystem. The RHEL packaging needs EPEL, which nothing here sets
up, so anything that is not Alpine dies with a clear message rather than
half-installing somewhere untested.

Three decisions worth recording:

The include chain is stubbed. knot.conf include:s seven files the `dns` repo
owns; Knot treats a missing include as a config error, so a node the pipeline
has never delivered to would fail conf-check and never start. deploy.sh
writes a placeholder for each one that is ABSENT -- never over a delivered
file -- so the node comes up healthy serving no zones until the pipeline
lands.

TSIG is generated on a primary and required on a secondary. The keys must
match byte for byte, so a secondary that generated its own would
authenticate nothing; it now refuses to deploy without TSIG_AUTHORITIVE and
TSIG_ADMIN. A primary generates both and prints them once. An existing
secrets.conf is never rewritten, so a re-run cannot rotate a key out from
under a running estate.

PRIMARY_ADDR seeds a minimal remotes.conf on a secondary so it can bootstrap
by AXFR before the pipeline runs -- written only when remotes.conf was
absent, verified by re-running against a delivered file and confirming it is
left untouched.

Re-runs apply changes rather than freezing at first deploy, per the pattern
this repo just adopted elsewhere: knot.conf is re-rendered from .env every
run, env-presence is captured before the ":=" defaults, and values passed to
a re-run are written back to .env with the awk-based set_env from 947c899 --
which matters here because a TSIG secret can contain the characters that
broke the sed-based one.

Two bugs caught while testing this, before it shipped:
- the secrets.conf renderer used `++n` as a gsub argument, which awk
  evaluates on every line, not just matching ones -- both keys would have
  received the SAME secret, making the read-only admin key identical to the
  replication key. Increments on a matching line only now.
- the MOTD is a pre-drawn box, so substituting values of a different width
  than their @TOKEN@ shifted the right border on every login. Values are now
  padded to the token's span, measured over an ASCII-only region so it holds
  under busybox awk in the C locale; an over-long value overflows rather than
  being truncated.

Verified: knot.conf renders identity/NSID/listen and leaves the control
socket alone; all seven stubs are created on a fresh node and skipped on a
re-run; the remotes.conf seed fires only for a fresh secondary; .env seeds
every runtime key; the MOTD renders with no leftover tokens and an aligned
border. Not verified: apk, knotc and the service start, which need an actual
Alpine host.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-16 14:32:45 -05:00
..

knot-dns

Authoritative DNS node — Knot DNS on Alpine, native (no container), for a global anycast estate with automatic DNSSEC.

Exception to the repo norm, alongside squid and openbao: no Docker, no Caddy, no Let's Encrypt. Knot binds :53 directly, needs real client addresses for RRL and DNS cookies, and its DNSSEC key store must live on the host filesystem. Containerising it buys nothing and costs the host firewall.

What this deploys, and what it does not

This stands up a node. It does not manage zones — that is the dns repo, and its pipeline delivers zone data here.

The split point is /etc/knot/knot.conf. This deployment writes it once as a skeleton of include: lines covering only what belongs to a box: identity, NSID, storage paths, listen addresses, logging, control socket. Everything that belongs to DNS policy — templates, DNSSEC policy, remotes/ACLs, modules, the domain inventory, the zone files — arrives from the dns repo.

Deployed here, once Delivered by the dns repo, continuously
knot.conf skeleton templates.conf, policy.conf, remotes.conf, modules.conf
secrets.conf (TSIG, rendered locally, never in git) dnssec.conf, public.conf, arpa.conf
knsctl, aliases, MOTD, zone.tmpl zones/**/*.zone
packages, users, directories, firewall

Files

File Purpose
deploy.sh The installer. Alpine only, native. Self-contained: the files below are embedded: rebuild with build.sh after editing them.
.env.example Seeds /etc/knot/.env. knot.conf is re-rendered from it every run.
cloud-init.yml Fresh-VM user-data: harden SSH, host firewall, then deploy.
knot.conf Bootstrap skeleton. @NODE_ID@ / @LISTEN@ substituted from .env.
secrets.conf.example TSIG key: block. Rendered to /etc/knot/secrets.conf, 0640 root:knot. Never committed.
knsctl Admin CLI. Replaces adddns.pl / adddnssec.pl and fixes four defects in them.
knotdns-aliases.sh /etc/profile.d/ — the existing muscle memory, with -b added everywhere.
knot-dns.motd The cheat-sheet MOTD.
zone.tmpl New-zone skeleton (mirrors dns/skeleton/zone.tmpl).

What deploy.sh does on a fresh node

Two things are worth knowing before the first run.

The include chain is stubbed. knot.conf include:s seven files this deployment does not own (remotes, policy, modules, templates, arpa, dnssec, public). Knot treats a missing include as a config error, so a node the dns pipeline has never delivered to would fail conf-check and never start. deploy.sh writes a placeholder for each one that is absent — and only for those, so a delivered file is never clobbered. The node therefore comes up healthy, serving no zones, until the pipeline lands.

TSIG keys are generated on a primary and copied to a secondary. They have to match byte for byte or nothing authenticates, so a secondary cannot invent its own. ROLE=primary generates both keys, writes secrets.conf and prints them once at the end of the run — capture them. ROLE=secondary requires TSIG_AUTHORITIVE and TSIG_ADMIN and refuses to deploy without them. An existing secrets.conf is never rewritten, so a re-run cannot rotate a key out from under a running estate.

A secondary also gets a minimal remotes.conf seeded from PRIMARY_ADDR, so it can bootstrap by AXFR before the pipeline has ever run. That seed is written only when remotes.conf was absent; once the pipeline owns the file, re-running leaves it alone.

Re-running is safe and is how you change things: knot.conf is re-rendered from .env every time, and values passed to the re-run are written back to .env first, so a corrected NODE_ID or LISTEN actually takes effect. Values you do not pass are left as they are.

Roles

ROLE in .env selects what the node is:

  • primary — holds zone files, signs with automatic DNSSEC, owns the KASP database, notifies the secondaries. Exactly one node. Not necessarily public-facing: a hidden (stealth) primary is the recommended shape.
  • secondary — receives zones by AXFR/IXFR with TSIG, serves queries, signs nothing. dnssec-signing must be off; a secondary serves data that is already signed.

Adding a public node is a secondary deploy plus one address in the primary's remotes.conf. With catalog zones configured, the new node self-populates.

What survives from the previous setup

Everything an operator types. knrl, knsc, knzc, knpbz, knsec, knarpa, ozf all still work, from the same paths, on the same box. Three corrections were folded in:

  1. -b on every triggering knotc command. Without it knotc returns OK when the command was sent, not when it succeeded, so a rejected zone file reports green. knrl was a bare knotc reload.
  2. knzr (zone-reload) added next to knrl (reload). Reloading one zone's data is the right verb for a record change — smaller blast radius, and a parse error in one zone cannot disturb the others. knrl reloads configuration and is only needed when a zone is added or removed.
  3. knsctl replaces the Perl scripts, whose duplicate check searched for the domain in BIND named.conf double-quote syntax against unquoted YAML and therefore never matched; which never consulted the other class's manifest, so a domain in public.conf could be appended to dnssec.conf and fail the reload after both files were already written; and which reloaded without validating.

Key material

/var/lib/knot/keys (the KASP LMDB) is node-local to the primary and replicates nowhere. Losing it is the one unrecoverable failure in this system: Knot will happily generate fresh KSKs, every published DS will point at keys that no longer exist, and every signed domain goes bogus until each registrar is updated by hand.

knotc -b zone-backup +backupdir /var/backups/knot/$(date -u +%FT%H) +journal

+journal is not the default — the documented default filter set excludes it, and in this configuration the journal holds the only durable copy of the signed zone and the last real SOA serial. A default zone-backup captures your keys and loses your zone data. Restore order is config → KASP + journal → then start knotd, never the reverse.

Usage

# interactive
bash deploy.sh

# non-interactive (this is what cloud-init.yml does)
ROLE=secondary NODE_ID=ANYCAST-DNS-3 PRIMARY_ADDR=10.1.24.64 \
    SKIP_PROMPTS=1 bash deploy.sh