Route consul API hostname to the HTTP API (8500) (#282)

Phase 2 of the consul migration: expose the HTTP API (not just the UI) at consul.k8s.syd1.au.unkin.net, now rebased onto main post-#280 (ACLs enabled).

- Adds a consul-http ClusterIP service targeting the server pods on 8500 (API + UI share the port, so the UI stays reachable at /ui/)
- Repoints the consul and consul-svc HTTPRoutes from consul-ui:80 to consul-http:8500
- Documents ACL-authenticated access in apps/base/consul/README.md: token from kv/kubernetes/namespace/consul/default/bootstrap-acl-token (VSO-synced), X-Consul-Token curl and consul CLI usage, UI token login, and the prefer-vault-minted-tokens note

Verification post-merge (ACLs are live, so authenticated): CONSUL_HTTP_TOKEN=$(vault kv get -field=token kv/kubernetes/namespace/consul/default/bootstrap-acl-token) && curl -H "X-Consul-Token: $CONSUL_HTTP_TOKEN" https://consul.k8s.syd1.au.unkin.net/v1/status/leader

Rollback: revert the HTTPRoute backends to consul-ui:80.
Reviewed-on: #282
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

apps/base/consul/README.md

@@ -0,0 +1,30 @@
+# consul (k8s)
+
+Consul server cluster (DC `au-syd1`), deployed via the HashiCorp helm chart with
+ACLs enabled (`default_policy: deny`, parity with the VM cluster).
+
+## API access (ACL auth)
+
+The HTTP API and UI are served on port 8500 behind the gateway at
+`https://consul.k8s.syd1.au.unkin.net` (and `https://consul.service.consul`).
+With ACLs enabled, requests beyond the anonymous policy require a token:
+
+```bash
+# management (bootstrap) token — seeded from Vault, synced by VSO into the
+# consul-bootstrap-acl-token secret; same value as the VM cluster's
+# initial_management token:
+CONSUL_HTTP_TOKEN=$(vault kv get -field=token kv/kubernetes/namespace/consul/default/bootstrap-acl-token)
+
+curl -H "X-Consul-Token: $CONSUL_HTTP_TOKEN" https://consul.k8s.syd1.au.unkin.net/v1/status/leader
+
+# consul CLI:
+CONSUL_HTTP_ADDR=https://consul.k8s.syd1.au.unkin.net CONSUL_HTTP_TOKEN=$CONSUL_HTTP_TOKEN consul members
+```
+
+The UI at the same hostname exposes an ACL login (top right) — paste a token.
+Anonymous requests get the anonymous-token policy only (reads for DNS/service
+discovery; no writes, no ACL/token APIs).
+
+Prefer short-lived tokens minted by Vault's consul secrets engine over the
+management token for day-to-day use; the terraform-* CI roles already work this
+way.

apps/base/consul/httproute.yaml

@@ -46,8 +46,8 @@ spec:
     - backendRefs:
         - group: ""
           kind: Service
-          name: consul-ui
-          port: 80
+          name: consul-http
+          port: 8500
           weight: 1
       matches:
         - path:
@@ -74,8 +74,8 @@ spec:
     - backendRefs:
         - group: ""
           kind: Service
-          name: consul-ui
-          port: 80
+          name: consul-http
+          port: 8500
           weight: 1
       matches:
         - path:

apps/base/consul/kustomization.yaml

@@ -6,5 +6,6 @@ resources:
   - namespace.yaml
   - gateway.yaml
   - httproute.yaml
+  - service.yaml
   - vaultauth.yaml
   - vaultstaticsecret.yaml

apps/base/consul/service.yaml

@@ -0,0 +1,25 @@
+---
+# ClusterIP service targeting the consul server pods' HTTP API (8500).
+# The HashiCorp chart only ships consul-ui (also 8500 via the server pods)
+# and the headless consul-server; this named service gives the Gateway a
+# stable API backend. Consul serves both the HTTP API and the UI (at /ui/)
+# on this same port, so routing the API hostname here preserves the UI too.
+apiVersion: v1
+kind: Service
+metadata:
+  name: consul-http
+  namespace: consul
+  labels:
+    app.kubernetes.io/name: consul
+    app.kubernetes.io/instance: consul
+spec:
+  type: ClusterIP
+  selector:
+    app: consul
+    component: server
+    release: consul
+  ports:
+    - name: http
+      port: 8500
+      protocol: TCP
+      targetPort: 8500