# `phoenixd`

Deploys and runs [phoenixd](https://phoenix.acinq.co/server), an ACINQ Lightning
node, on the edge host. LNBits uses it as a wallet backend. The HTTP API stays on
loopback — phoenixd is never published through Caddy.

Converted from `deploy_phoenixd_playbook.yml` (552 lines) under Plan 6. The
playbook is now 18 lines.

## Phases

| | |
|---|---|
| `install.yml` | packages, system user, directories, versioned download and install |
| `service.yml` | systemd unit, start, then first-boot checks (config written, seed created) |
| `healthcheck.yml` | check script, unit, timer |

## The seed

`{{ phoenixd_data_dir }}/seed.dat` **is** the funds. phoenixd is deliberately
excluded from the automated backups (Plan 5, Model C): the seed is twelve fixed
words that never change, so an automated job would only manufacture more copies
of a static secret on more machines. Write them down offline, once.

Note the live file is mode `0644`. That is phoenixd's own doing, not this role's,
and it is worth tightening.

## Monitoring: one variable, no product knowledge

The check asks the node itself — the service must be active **and**
`phoenix-cli getinfo` must return a `nodeId` — and records the answer in its exit
code, which systemd keeps:

```bash
systemctl is-failed phoenixd-healthcheck.service
```

That is a complete answer with no monitoring system involved. To report
elsewhere, set `healthcheck_push_url` to anything accepting an HTTP ping. Gone
from this role: the embedded Python that created monitors over the Uptime Kuma
API, the `/tmp` credentials file, the push-URL file written and parsed back, and
the systemd `Environment=` rewrite.

### Two things the conversion fixed

**The check used to log an error once a minute.** Its `Environment=` push URL had
been empty since the decommissioning, and the script printed
`ERROR: UPTIME_KUMA_PUSH_URL not set` on every fire — roughly 1,400 times a day.
The exit code was still correct, so nothing was broken; it was pure noise, and
noise that trains you to ignore the log. An unset push URL is now normal and
silent.

**`Enable and start phoenixd health check timer` was guarded by
`uptime_kuma_enabled`** and so had not run since the decommissioning — while the
timer itself was still live on the host from before. Ansible had quietly stopped
managing something that was still running. Ungated.