# time-sync

The machine's clock, kept by one daemon: systemd-timesyncd (novox/hq to-be 42 Phase 1,
research 027).

## What it owns

- `/etc/systemd/timesyncd.conf.d/50-mesh.conf`, written whole: `NTP=` the four European pool
  servers, `FallbackNTP=` the distribution's pool.
- `systemd-timesyncd.service`, running and enabled, and restarted when the drop-in changes.
- `ntp`, declared **absent** (ADR 0180).
- A **step**, `time-sync-retire-ntpd`. The host runs the module's own binary once per version of the
  bundle, as root, *before* timesyncd is started and ntp removed:
  `time-sync-tools retire ntpd.service ntpdate.service`. The step stops and disables each unit that
  is installed and running or enabled. Removing a package does not disable its units, so without the
  step ntp's removal would leave `multi-user.target.wants/ntpd.service` pointing at nothing. Where
  the package is already gone, the step takes out only such a dangling link, never a link it can
  still follow.

## What it improves

- One daemon on every machine. Three ran timesyncd and one ran ntpd, with timesyncd disabled.
- The servers are declared, not left to whatever a machine was installed with. One machine had
  edited `timesyncd.conf` itself; the drop-in now overrides that.

## What it leaves found

- **A hosting provider's own drop-in.** On a machine whose provider installed a timesyncd drop-in
  (found on the anchor), that file sorts after `50-mesh.conf`, so its servers win. They are in the
  same network as the machine. It is kept, and `time_sync_servers` names it as the file that decides.
- `/etc/systemd/timesyncd.conf`, and an `/etc/ntp.conf` that the package manager keeps as `.pacsave`.

## Tools

| tool | | answers |
|---|---|---|
| `time_sync_status` | r | synchronised, NTP on, timesyncd's unit; server, offset, delay, jitter (ms), stratum, packets, and every line of `timesync-status`; any other time daemon installed. If timesyncd is not running, that is said, not failed |
| `time_sync_servers` | r | the server in use; system, fallback, link and runtime servers; every config file in reading order with what it sets; which file decides |
| `time_sync_sync_now` | a | restarts timesyncd (sudo -n) and answers the status after waiting up to 10 s for a packet |