Outpost

Outpost is a host health daemon. It polls external HTTP targets and exposes their status over a small HTTP API. It can also schedule a delayed, cancellable restart or shutdown of the host it runs on.

Why outpost

• Single-host by design.
  • Most monitoring stacks watch many hosts and services. Outpost is for the one host nobody else is watching like a self-hosted server, a VM host, or an edge device.
• Zero dependencies.
  • It is one static Go binary and a YAML config file. No database, no agents, no external services. It sits behind any reverse proxy or is reached directly.
• Recovery primitive, not a platform.
  • The point is "is the thing I rely on still answering, and can I kick it". HTTP probing plus a delayed, cancellable restart and shutdown lets you rescue a wedged host from another device. Metrics are live gauges only; the daemon stores nothing.
• Deliberately small scope.
  • No metrics storage, no alerting, no dashboards. It only exposes live state over /metrics for an existing Prometheus to scrape.

Features

• Probes all targets concurrently on a fixed interval. Up means any 2xx or 3xx response.
• JSON /status and /health endpoints, optionally public.
• Prometheus /metrics endpoint, gated like /status.
• Actions gated by an API key sent as an Authorization: Bearer header, minimum 32 characters.
• Delayed, cancellable host restart and shutdown via systemctl.
• Append-only JSONL event log of all scheduled and fired actions.

Install

Requires Go 1.26.

go build -o outpost .

Prebuilt binaries are published on releases and packaged for Arch Linux as the outpost AUR package.

Configuration

Copy config.example.yaml to /etc/outpost/config.yaml and edit it. By default outpost

• listens on :8080,
• probes every 30s with a 10s minimum,
• keeps /status, /health and /metrics key-free since public_status defaults to true,
• writes events to /var/log/outpost/events.jsonl.

The config path comes from the -config flag, falls back to $OUTPOST_CONFIG, and then to /etc/outpost/config.yaml.

API

Method	Path	Auth	Notes
GET	/health	only with public_status: false	Returns {"status":"ok"}.
GET	/status	only with public_status: false	Probe snapshot. Reports up and total, per-target results, and an overall status of unknown, up, down, or degraded.
GET	/metrics	only with public_status: false	Prometheus text format. Per-target outpost_probe_up and outpost_probe_last_check, overall outpost_probe_targets / outpost_probe_targets_up, plus Go runtime and process metrics.
POST	/restart	required	Body {"reason":"..."} is optional. Returns HTTP 202 with the action name and its delay in seconds. Answers 409 when one is already pending.
POST	/shutdown	required	Same as /restart.
POST	/cancel	required	Body holds "action" set to "restart" or "shutdown". Answers 404 when nothing is pending.
GET	/events	required	Event log entries, newest last. ?limit=N caps the count.

Example:

curl -H "Authorization: Bearer $(cat /etc/outpost/api_key)" \
  -d '{"reason":"updating packages"}' http://localhost:8080/restart

Auth

Actions require a Bearer token read from api_key_file. When the file is missing or the key is shorter than 32 characters, the action endpoints answer 503. The daemon keeps serving status, so a bad key is safe degradation rather than a startup failure.

Actions

On Linux, restart runs systemctl reboot and shutdown runs systemctl poweroff. Only one action of each kind may be pending at a time. The event is written to the log before the command fires, since a successful reboot or poweroff usually kills the process. On other platforms actions are unsupported and answer 503.

systemd

A unit file is included at packaging/systemd/outpost.service.

License

AGPL-3.0