oikos/infrastructure/mesh.md

# Mesh — Tailscale → Netbird migration

The hubris fleet is migrating from Tailscale to Netbird. Netbird is the target end-state. In-progress as of 2026-04-21.

## Current state

- **PVE host** uses Netbird (`wt0`, `100.122.38.109/16`). Its resolver is the local netbird daemon, which forwards to LAN/upstream — so the PVE host gets `*.hubris.network → 192.168.8.175` via the system resolver chain.
- **Netbird mgmt host** (`82.165.190.79`, FQDN `inspiring-ramanujan.netbird.selfhosted`, NB IP `100.122.165.149`) is now itself a peer on the mesh (joined 2026-04-22 via setup key, netbird 0.69.0). Routes the homelab network (`192.168.8.0/24`) via the PVE peer. This gives the mgmt host LAN access *and* split-horizon DNS for `*.hubris.network`. Useful independently of any Authentik integration.
- **Most LXCs** still run Tailscale or use router DNS (`192.168.8.1`) / Tailscale MagicDNS (`100.100.100.100`), both of which return the *public* IONOS A record `*.hubris.network → 82.165.190.79`. The VPS only routes hostnames it actually publishes (today, `artifacto` + `blog`), so this path is a dead end for any LAN-only service.

## ICE / STUN / TURN

**Today** (post-2026-05-21 migration):

- External STUN servers (Google + Cloudflare) declared under `server.Stuns` in `/opt/management.json`. Embedded STUN is no longer in use.
- coturn runs on the VPS host (apt-installed, systemd-managed). TURN URL `turn:netbird.hubris.network:3478?transport=tcp` is advertised to peers via mgmt's `TURNConfig.Turns` block. Long-term credentials at `user=netbird:<pwd from /root/turn-pass.txt>`.
- For non-symmetric peers, ICE picks direct `srflx/srflx` (P2P). For symmetric-NAT peers, ICE falls through to TURN-relay before falling back to the WSS relay (`rels://netbird.hubris.network:443`).

**IONOS port-3478 caveat** (load-bearing — undocumented before 2026-05-21):

IONOS upstream filters STUN-class traffic on port 3478 **for both UDP and TCP** by default. The UDP block was already known (verified 2026-05-10 with `tcpdump -ni any udp port 3478`). The TCP block was discovered 2026-05-21 when TURN-allocate retries timed out from a symmetric-NAT laptop: TCP handshake completed (carried by kernel-only SYN exchange) but data packets never reached the VPS's `ens6` interface.

**Resolution**: operator must add an inbound firewall exception in the IONOS dashboard (Cloud Panel → Networks → Firewall policy on the VPS) for inbound TCP 3478 (and UDP 3478 if STUN-via-VPS-listener is ever needed; we use external STUN so this is optional). Without that exception, coturn is unreachable from outside even though host nftables + listener look fine.

**Verifying TURN works** end-to-end from an outside peer:

```python
# python3
import socket, struct, secrets
s = socket.create_connection(("netbird.hubris.network", 3478), timeout=10)
tid = secrets.token_bytes(12)
attrs = struct.pack("!HHI", 0x0019, 4, 17 << 24)   # REQUESTED-TRANSPORT = UDP
msg = struct.pack("!HHI", 0x0003, len(attrs), 0x2112A442) + tid + attrs  # Allocate
s.sendall(msg)
print(s.recv(4096).hex())  # expect 120 bytes starting 0x0113 (Allocate Error = auth challenge)
```

A 120-byte `0x0113`-typed response means coturn is reachable and responding. An indefinite TCP timeout (after `connected from ...` prints) means the IONOS rule was reverted or narrowed.

**If a peer is still on the WSS relay after this** — verify in `netbird status -d`: `Connection type: P2P` with srflx/srflx is the cone-NAT happy path; `Connection type: P2P` with relay/srflx (or relay/prflx) means the peer's network is symmetric-NAT and it's using TURN. Falling back to `Relayed (rels://...)` only happens if TURN allocate also fails — investigate the IONOS exception first.

**Old combined-server note (history, kept for context):**

Pre-migration, the bundled `netbirdio/netbird-server` combined image silently ignored both `server.turns:` and top-level `TURNConfig:` YAML, so TURN was non-functional. That's why the architectural migration to the canonical multi-container stack (`mgmt + signal + relay + coturn`) happened. See the 2026-05-21 changelog entry below and the [Netbird-combined-no-TURN finding](https://github.com/netbirdio/netbird/issues) in homelab memory for the full discovery.

## Consequence — every LXC wired to Authentik needs an internal override

Until each LXC is migrated to Netbird, anything that needs to reach `auth.hubris.network` (Authentik), `cloud.hubris.network` (Nextcloud), etc., must override the public answer with `192.168.8.175`.

Two techniques. Pick by HTTP-client behavior.

### A) `/etc/hosts` override

Works for libc `getaddrinfo` clients: curl, wget, most Go/Python/Ruby apps, gitea.

- Place the line **outside** the `# --- BEGIN PVE ---` / `# --- END PVE ---` markers. Proxmox rewrites everything inside that block on every container start.
- Belt-and-suspenders: `/etc/systemd/system/hubris-hosts-override.service` (oneshot, enabled, idempotent).

### B) Local dnsmasq

Required for clients that bypass `/etc/hosts`. **Nextcloud (PHP Guzzle + `OC\Http\Client\DnsPinMiddleware`) is one** — uses `dns_get_record()`, not `getaddrinfo`. Likely candidates for the same treatment: Python/Ruby/Java apps that do explicit DNS resolution before connecting.

Recipe:
```
apt install dnsmasq

cat > /etc/dnsmasq.d/hubris-internal.conf <<EOF
address=/auth.hubris.network/192.168.8.175
server=192.168.8.1
server=1.1.1.1
interface=lo
bind-interfaces
no-hosts
no-resolv
EOF

# Set LXC default nameservers and live resolv.conf
pct set <id> --nameserver "127.0.0.1 192.168.8.1 1.1.1.1"
# Then update /etc/resolv.conf inside the LXC too.
```

### Known overrides applied

| LXC                                        | Technique                                | Notes |
| ------------------------------------------ | ---------------------------------------- | ----- |
| [104 (gitea)](../containers/104-gitea.md)  | `/etc/hosts` + `hubris-hosts-override.service` | Standard |
| [114 (nextcloud)](../containers/114-nextcloud.md) | local dnsmasq @ 127.0.0.1 + resolv.conf reorder | Guzzle bypasses /etc/hosts |
| [105 (apps)](../containers/105-apps.md), inner containers | `extra_hosts:` in compose | Booklore, mulita, WriteFreely each ship with this |

## Adding new LXCs

- Don't add new LXCs to Tailscale; add them to Netbird. Tailscale is being decommissioned on hubris.
- When wiring a new app into Authentik: `cat /etc/resolv.conf` on the target LXC. If nameserver is `192.168.8.1` or `100.100.100.100`, add the hosts override. If it's the netbird daemon IP, skip.

## Long-term fix

Either:
- Split-horizon DNS at LAN/router level so `*.hubris.network → 192.168.8.175` for every LAN client. Eliminates all per-LXC overrides.
- Once Netbird migration completes, every LXC's resolver becomes the netbird daemon, which already learns hubris.network answers via the system resolver chain on the PVE host.

## CRITICAL — never `docker compose up` Portainer-managed stacks

[apps (105)](../containers/105-apps.md) runs multiple stacks deployed via the Portainer UI (`/var/lib/docker/volumes/portainer_data/_data/compose/<N>/`). Running `docker compose up -d <svc>` from the host shell on these triggers a recreate of OTHER services in the stack — labels drift, compose treats the project as reconciling, containers get destroyed and remade. **This wiped Booklore's mariadb data on 2026-04-22** (bind mount `./mariadb/config` re-initialized fresh).

Recipe for container-config changes (e.g. adding `extra_hosts`) on Portainer-managed stacks:
1. Edit the compose in Portainer UI → **Stacks → <stack> → Editor → Update stack**. Portainer handles the recreate cleanly with its own state tracking.
2. Do NOT edit `/var/lib/docker/volumes/portainer_data/_data/compose/<N>/docker-compose.yml` directly.
3. For data-preserving DNS overrides on stateful services, prefer Caddy-side handling (forward-auth) or the app's built-in OIDC over container-level `extra_hosts` when possible.

## Related
- [DNS split-horizon](dns.md)
- [Authentik (124)](../containers/124-authentik.md) — the IdP that triggers most of these overrides
- [Nextcloud (114)](../containers/114-nextcloud.md) — example of Technique B
- [Gitea (104)](../containers/104-gitea.md) — example of Technique A
- [Public ingress (VPS traefik)](ingress.md) — uses the same mesh as transport

## Changelog

### 2026-05-21 — VPS migrated combined → vanilla netbird stack with external TURN
The combined `netbirdio/netbird-server` image was replaced with the canonical multi-container deploy (`netbirdio/management:0.71.3` + `signal:0.71.3` + `relay:0.71.3` + `dashboard:latest` + host coturn) on `/opt/docker-compose.yml`. Driver: combined image silently ignored external `TURNConfig` so symmetric-NAT peers couldn't use TURN.

Same migration also swapped OIDC from the combined image's embedded Dex IdP to Authentik on [LXC 124](../containers/124-authentik.md), upgrading mgmt to 0.71.3. The `store.db` schema auto-migrated cleanly from 0.68.3 (copy-not-move from the old `opt_netbird_data` volume into the new `mgmt_data` volume). Pre-cutover backups at `/root/netbird-*.tgz` on the VPS, ~857 MB, retained for ~7d.

Also during this work: IONOS upstream was found to filter TCP 3478 in addition to UDP 3478. Added a TCP-3478 inbound exception in the IONOS firewall (see ICE/STUN section above for the verification probe).

The new Authentik provider for NetBird is `Client type: Public` (PKCE-only). Confidential would break the dashboard SPA's token exchange. The Device Code grant flow is wired (see [containers/124-authentik.md](../containers/124-authentik.md#device-code-grant--configured-2026-05-21)) so interactive `netbird up` works — `--setup-key` is no longer required for new peers.

**Post-migration JWT-issuer gotcha on existing peers** (cost ~30 min to diagnose 2026-05-21):

Existing peers — registered against the old combined image's embedded Dex IdP at `https://netbird.hubris.network/oauth2` — cache the OLD expected SSH-JWT issuer in the netbird daemon's in-memory state. After the migration, incoming `netbird ssh` connections were rejected with:

```
JWT authentication failed: validate token (
  expected issuer=https://netbird.hubris.network/oauth2,
            audiences=[netbird-dashboard netbird-cli],
  actual    issuer=https://auth.hubris.network/application/o/netbird/,
            audience=netbird-dashboard
)
```

Neither `systemctl restart netbird` nor `netbird down && netbird up` clears the cache. Root cause: in `client/internal/engine_ssh.go`, `updateSSH()` bails out with `if e.sshServer != nil { return nil }` whenever the SSH server is already running, so mgmt-pushed JWT config updates are silently ignored. Only a full daemon-process tear-down lets the SSH server re-initialize with the new validator config:

```
sudo systemctl stop netbird
sleep 3
sudo systemctl start netbird
```

After that, `grep -iE "issuer|audience" /var/log/netbird/client.log | tail` shows the new Authentik issuer. Run this on every existing peer (PVE host + every LXC + every workstation) once after a future IdP swap.

**Username gotcha (related):** `netbird ssh` defaults the remote username to the LOCAL one (e.g. `dtoro` from the operator's laptop). Hubris + the LXCs only have `root`, so the JWT is accepted but the session immediately fails with `user dtoro not found`. Always use the explicit `root@` prefix when invoking netbird-ssh manually:

```
netbird ssh -p 22022 root@proxmox-server.netbird.selfhosted
```

The `homelab` CLI handles this automatically via the per-host `ssh.user` field in `inventory.yaml` (defaults to `root`; set explicitly only for workstations whose login user isn't `root`).

Open follow-up: TURN-over-TLS on TCP 5349 (cert via certbot or extract Traefik's acme.json) for hostile-middlebox networks; plain TCP 3478 is sufficient for current usage.

### 2026-05-10 — ICE direct p2p restored (external STUN swap)
All peers were `Connection type: Relayed` because the embedded STUN on the VPS was unreachable from outside (IONOS drops UDP 3478 inbound). Swapped to Google + Cloudflare STUN in `/opt/config.yaml`. After `netbird down/up`, peers now report `P2P` with srflx/host candidates. Backup of pre-change config at `/opt/config.yaml.bak-20260510-185050`. Fixes a real-world Nextcloud upload bottleneck (~366 kB/s through the relay → LAN-direct on same-network peers).

### 2026-04-28 — wiki entry created
Initial documentation.

### 2026-04-22 — Booklore mariadb data wiped (lesson recorded)
The "never docker compose up Portainer-managed stacks" rule comes from this. See [apps (105)](../containers/105-apps.md#changelog).

### 2026-04-22 — netbird mgmt host joined its own mesh
`82.165.190.79` is now a peer (`100.122.165.149`). LAN access + split-horizon DNS via PVE peer. See [VPS hardening](vps-hardening.md).

### 2026-04-21 — overrides applied to gitea (104) and nextcloud (114)
Two techniques documented; Nextcloud forced the dnsmasq route because of Guzzle.