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# Routing TaPPaaS through the VPS

### Split-horizon DNS · public exposure on a static IP

MakerFLOSS · June 2026 · _technical review_

---

## The goal

Publish selected **TaPPaaS** web services under `*.tappaas.makerfloss.eu`.

- **Public exposure** — A records point at the VPS static IP `88.99.32.236`,
  so the cluster's services are reachable from anywhere.
- **Split-horizon DNS** — the _same_ hostname resolves to a **local** address
  for internal clients, so they never round-trip to the VPS.
- **Isolation preserved** — nothing on the makerspace side egresses through
  the VPS or reaches the homelab.

> We are not inventing anything — we clone a pattern already running.

---

## Building block: the proven `mf01` pattern

`mf01` already publishes `*.mf01.makerfloss.eu` exactly this way, live since
2026-06-09:

- TLS terminates on the **VPS** (wildcard cert, Gandi DNS-01).
- Plain HTTP rides the **`wg1`** WireGuard tunnel to an internal reverse proxy.
- The internal proxy routes by **Host** to the right container.

**TaPPaaS = the same shape**, with Caddy as the internal proxy instead of an
internal Traefik. Low risk, known gotchas already solved.

---

## External request flow

```mermaid
flowchart LR
  C["Browser<br/>(off-site)"] -->|"https · *.tappaas<br/>DNS → 88.99.32.236"| T["VPS Traefik :443<br/>wildcard cert<br/>TLS ends here"]
  T -->|"plain HTTP<br/>inside wg1"| K["FLOSSFirewall / Caddy<br/>10.13.0.9:80"]
  K -->|"route by Host"| S["TaPPaaS service<br/>srv01 / srv02 / srv03"]
```

TLS terminates at the VPS; the backend hop is plain HTTP but **encrypted on the
wire inside WireGuard**.

---

## Internal flow — two views, one name

```mermaid
flowchart TD
  N["&lt;svc&gt;.tappaas.makerfloss.eu"]
  N -->|"public DNS (Gandi)"| V["VPS 88.99.32.236<br/>VPS wildcard cert"]
  N -->|"internal DNS (FLOSSFirewall)"| L["Caddy local IP<br/>Caddy's own LE cert"]
```

A client only ever sees the cert for the IP it resolved — **VPS wildcard
externally, Caddy's own cert internally**. The two views never collide.

---

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## Key decisions

| Decision | Choice | Why |
|---|---|---|
| Transport | New **`wg1`** WireGuard peer | Mirrors mf01; both ends self-owned; static hub-and-spoke |
| TLS (external) | **Terminate at the VPS** | Cert issuance while isolated kills passthrough; Gandi DNS-write key stays on the VPS; keeps edge routing/middleware |
| Naming | **Wildcard** `*.tappaas.makerfloss.eu` | One cert + one route; add services with zero VPS change; no apex clash (`forgejo.tappaas…` ≠ `forgejo.makerfloss.eu`) |
| Internal DNS | **FLOSSFirewall** (already runs DNS), cluster first | LAN view deferred — depends on third-party router |

---

## Components — VPS side

All additive in `AnsibleBaobabV4/host_vars/makerfloss.yml`, mirroring mf01:

1. **wg1 peer** — FLOSSFirewall, `allowed_ips: 10.13.0.9/32`.
2. **Wildcard cert** — add `tappaas.makerfloss.eu` + `*.tappaas` to
   `traefik_wildcard_sets` → ACME anchor issues it via Gandi DNS-01.
3. **Catch-all route** — `tappaas-delegate.yml`:
   `HostRegexp(...tappaas...)` → `http://10.13.0.9:80`, `passHostHeader: true`.
4. **Public DNS** — `tappaas` + `*.tappaas` A → `88.99.32.236`.

After this, **new services need zero VPS change** — exposure is decided at Caddy.

---

## Components — TaPPaaS / Caddy side

1. **WireGuard client** — peer to the VPS hub, interface `10.13.0.9/32`,
   `AllowedIPs = 10.13.0.0/24` only → **split-tunnel** (no general egress
   through the VPS).
2. **Caddy plain-HTTP backend** — Host-routed listener on the wg interface
   (`10.13.0.9:80`), **HTTPS-redirect OFF**. Caddy keeps serving `:443` with its
   own certs to internal clients, unchanged.
3. **Firewall** — allow `tcp/80` **only from `10.13.0.1`** (the VPS) on the wg
   interface.

---

## Phasing — five verifiable steps

1. **Tunnel** — FLOSSFirewall up as `wg1` peer; ping `10.13.0.1 ↔ 10.13.0.9`.
2. **Caddy backend** — from the VPS,
   `curl -H 'Host: <svc>.tappaas.makerfloss.eu' http://10.13.0.9:80`.
3. **VPS edge** — add cert + route + DNS; off-site
   `curl https://<svc>.tappaas.makerfloss.eu` with a valid cert.
4. **Internal DNS** — add `*.tappaas` override; a cluster node resolves to
   Caddy's local IP and gets Caddy's own cert.
5. **(Later)** makerspace LAN view — conditional-forward + firewall pinhole on
   the OrangeMakers router.

---

## Isolation — the hard requirement

- **Split-tunnel** (`AllowedIPs = 10.13.0.0/24`) — the cluster never egresses
  through the VPS; nothing on `wg1` reaches the makerspace or homelab.
- VPS→Caddy locked to `tcp/80 from 10.13.0.1` on the wg interface.
- Backend hop encrypted inside WireGuard.
- **No public-DNS-write credential leaves the VPS** — the reason TLS terminates
  there, not via passthrough.

---

## Risks & open items

- **Caddy redirect** — the wg-interface listener must _not_ force HTTPS-redirect,
  or the VPS hits a loop (mf01's known gotcha).
- **YAML safety** — a syntax error in `tappaas-delegate.yml` breaks the whole
  VPS file provider; keep the regex single-quoted.
- **`10.13.0.9` free?** — confirm before assigning.
- **TaPPaaS config repo TBD** — the FLOSSFirewall/Caddy/DNS config home is not
  yet identified.
- **Phase 5** depends on OrangeMakers router cooperation.

---

## Summary & next steps

- Reuse the **proven mf01 pattern** — terminate TLS at the VPS, proxy over
  `wg1` to TaPPaaS Caddy, split-horizon DNS for the internal view.
- VPS side is a small, additive, **zero-new-tech** change.
- **Next:** identify the TaPPaaS config repo, then write the implementation plan
  and execute phases 1–4.

_Design: `MakerFLOSS_Troubleshooting/docs/superpowers/specs/2026-06-28-tappaas-vps-publishing-design.md`_
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