fix(node): pin gitea to the Gateway VIP — containerd was resolving it to the non-hairpinned WAN

The pm-agent image pull failed TLS verification, and the previous entry on this branch
recorded it honestly as not diagnosed. Diagnosed now, and it is not about the image.

containerd pulls as a NODE process, so it resolves through node_baseline_dns_servers (the
LAN gateway, deliberately not PiHole) and gets the public answer: a CNAME to
wan.home.keithjackson.dev -> 136.51.115.252, measured via both 1.1.1.1 and 8.8.8.8. This
router does not hairpin, so WAN:443 answers with its own placeholder certificate —
measured with the right SNI from the workstation:

    subject=C=ZZ, ST=Somewhere, L=Unknown, O=%D342e7e6b, CN=%D
    No extensions in certificate

No extensions means no subjectAltName, which is exactly 'certificate is not valid for any
names'. Meanwhile 192.168.2.20 IS the shared Gateway's VIP and its https listener serves
the real Let's Encrypt *.home.keithjackson.dev. The Gateway, the wildcard cert and the
digest were never implicated — only the node's answer.

This file already documents the identical failure for the Keycloak issuer, measured from
k3s-prod-2/-3 on 2026-10-03 (curl exit 60, ssl_verify_result=18), and already carries the
mechanism that fixes it. gitea is simply the second node process to need it; containerd is
a node process and nobody had added it. An operator must run the node_baseline play.

Also records, where an operator reads them, that the agent authenticates to Gitea with a
local account and a scoped PAT by decision — and why the federated alternative is not
merely unchosen but unavailable: Gitea implements only the Authorization Code Grant and
validates no third-party OIDC token, so a Keycloak service-account token cannot
authenticate to its API or to git-over-HTTP.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

decisions/2026-10-06-pm-agent-node-resolves-gitea-to-wan.md

@@ -0,0 +1,111 @@
+---
+date: 2026-10-06
+branch: docs/pm-agent-registry-pull-prereq
+title: The nodes resolve gitea to the WAN, so the failing certificate is the router's — the second node process to need the issuer pin
+---
+
+## What changed
+
+The image pull for `pm-agent` failed TLS verification, and the previous entry on this branch
+honestly recorded it as **not diagnosed**. The operator asked for the diagnosis before any
+registry design. This is it, and the fix turns out to be a pattern this repository already
+has.
+
+`infra/ansible/inventory/group_vars/k3s_prod/vars.yml` now pins
+`gitea.{{ k3s_base_domain }}` → `192.168.2.20` in `node_baseline_hosts_pins`, beside the
+Keycloak issuer pin that is there for the identical reason. **An operator must run the
+`node_baseline` play for it to reach the nodes** — writing `/etc/hosts` on a node is not
+something Flux or an agent can do.
+
+The docs that described this as an undiagnosed blocker now describe the cause and the fix:
+`platform/pm-agent/README.md`, `runbooks/pm-agent.md` (its symptom row now names the pin and
+the play), and `docs/plans/pm-agent-issue-to-pr.md`.
+
+Also recorded, in the two places an operator reads when creating the credential: **the agent
+authenticates to Gitea with a local account and a scoped PAT, by decision** (operator,
+2026-10-06), not with a federated identity. Written down because the alternative looks
+obviously better until you check whether it is possible — see below.
+
+## What I verified
+
+Every step measured, read-only, in this order.
+
+**The failing certificate is the router's, not the Gateway's.**
+
+- containerd's error names TLS, not the digest: `tls: failed to verify certificate: x509:
+  certificate is not valid for any names, but wanted to match gitea.home.keithjackson.dev`.
+  "not valid for **any** names" means the presented certificate carries no SANs at all.
+- `192.168.2.20` is the shared Gateway's own LoadBalancer VIP
+  (`gateway/cilium-gateway-shared`, from the Cilium pool `192.168.2.20-30`), and its `https`
+  listener serves `*.home.keithjackson.dev` with `wildcard-home-tls`. From the operator's
+  workstation the name resolves there and serves the real Let's Encrypt
+  `CN=*.home.keithjackson.dev` with correct SANs. **So the certificate and the Gateway are
+  healthy.**
+- **The node asks a different resolver and gets a different answer.** Prod's
+  `node_baseline_dns_servers` is the LAN gateway, not Pi-hole — deliberately, as that file
+  explains. Public DNS for this zone is a CNAME to `wan.home.keithjackson.dev`: measured via
+  both `1.1.1.1` and `8.8.8.8`, `gitea.home.keithjackson.dev` →
+  `wan.home.keithjackson.dev.` → `136.51.115.252`, and the apex answers the same.
+- **That address serves a certificate with no names.** Measured from the workstation against
+  the WAN address with the right SNI:
+
+      subject=C=ZZ, ST=Somewhere, L=Unknown, O=%D342e7e6b, CN=%D
+      issuer=C=ZZ, ST=Somewhere, L=Unknown, O=%D342e7e6b, CN=%D
+      No extensions in certificate
+
+  No extensions means no `subjectAltName`, which is exactly "not valid for any names". The
+  `CN=%D` is the router's placeholder.
+
+**This repository had already measured the same thing, for Keycloak, and I did not need to
+re-derive it.** `infra/ansible/inventory/group_vars/k3s_prod/vars.yml` says, above the pin:
+"Since platform/gateway/gateway.yaml set an external-dns `target`, every public name is a
+CNAME to wan.home.keithjackson.dev = the home WAN IP. The SOHO router does NOT hairpin: from
+the LAN, WAN:443 answers with the router's own self-signed placeholder cert (measured from
+k3s-prod-2/-3 2026-10-03: `curl` exit 60, ssl_verify_result=18)." Same cause, same symptom,
+one name later. The pin exists precisely for node processes that must reach the Gateway
+directly; containerd is one, and nobody had added it.
+
+**The parity the pin has to satisfy:** `192.168.2.20` equals the live
+`GATEWAY_VIP`, and `k3s_base_domain` equals the live `BASE_DOMAIN` — both read from the
+cluster, not from the comment that claims prod serves `prod.home.keithjackson.dev` (it does
+not; `flux-system/cluster-vars` reports `BASE_DOMAIN=home.keithjackson.dev` and
+`GATEWAY_VIP=192.168.2.20`, and Ansible's `k3s_base_domain` is `home.keithjackson.dev`).
+That comment is stale history.
+
+**The credential decision, and why the obvious alternative is not available.** Gitea's API
+accepts basic auth, PATs, SSH signatures and its own OAuth2 bearer tokens; as an OAuth2
+provider Gitea implements **only the Authorization Code Grant** (plus PKCE/OIDC), so there
+is no client-credentials grant, and nothing in Gitea validates a token issued by a
+third-party OIDC provider. A Keycloak service-account token therefore cannot authenticate to
+Gitea's API or to git-over-HTTP. Read from Gitea's own documentation
+(`docs.gitea.com/development/api-usage`, `/development/oauth2-provider`), not assumed.
+
+**Gate:** `./ci/gate.sh` in the pinned toolbox from a §0 worktree — see the branch's run; rc 3
+with `gitea-settings` the only stage that did not run.
+
+## What I did NOT verify
+
+- **That the pin fixes the pull.** It is IaC, and nothing has applied it: `/etc/hosts` on the
+  nodes is written by the `node_baseline` play, which is an operator action. Until that runs
+  and an image exists, "the node now reaches the Gateway" is a design claim. The evidence
+  that it *will* is the Keycloak pin working for the same cause — which I also did not
+  re-measure.
+- **Why public DNS answers at all for an `internal` service.** `catalog/gitea.yaml` sets no
+  `exposure`, so it inherits `internal`, and the renderer contract says an internal service's
+  HTTPRoute carries `external-dns.alpha.kubernetes.io/controller: none` and publishes no
+  public record. Yet `gitea.home.keithjackson.dev` resolves publicly to the WAN CNAME. I did
+  not chase that: it may be a zone-level wildcard rather than a published record, and it did
+  not change the diagnosis. It is worth someone's attention, because "internal services
+  publish no public DNS" is an L0-checked claim and this looks like a case where the *name*
+  resolves regardless of what the renderer withheld.
+- **Registry authentication.** Unchanged and still open: an unauthenticated client gets
+  nothing from this registry, and no `imagePullSecret` exists anywhere in the tree. With the
+  credential model now decided (local Gitea accounts with PATs) the shape is a
+  `dockerconfigjson` for an account whose token carries `read:package`, referenced from the
+  Deployment and the committed worker Job template — and the worker Job template's shape is
+  pinned by admission, so whether the policy should also pin `imagePullSecrets` deserves a
+  deliberate look rather than a quiet addition. Not built: minting that token is an operator
+  action, and I did not want to guess at a second credential's scope.
+- **Anything about runtime.** The image still does not exist. No dispatcher has
+  authenticated, no issue has been triaged, no worker Job has been created, and the admission
+  policy — live, `Enforce`, six rules — has still never admitted or refused a real Job.