# Systemd Timers for Regular Tasks

To have custom executables run regulary on given time/interval, you may use the `base::timers` Hiera key:

```
base::timers:
    'timer_test':
        description: 'test timers'
        command: '/usr/bin/logger foo'
        on_calendar: '*:*:10'
        timer_options:
            persistence:  false
```

For each timer following keys are mandatory

- `description` for a short explaination what it is about
- `command` for the command to run
- `on_calendar` defining when it should run using the [`systemd` calendar event format](https://www.freedesktop.org/software/systemd/man/systemd.time.html#Calendar%20Events), (alternatively see also chapter "CALENDAR EVENTS" of `man systemd.date`)

Optional is
- `timer_options` for additional options. In the example it is  `persistence`which signals if the timer should run immediately after boot when the node was switched of on the last scheduled run time (default is `false`).