---
tags:
  - Linux
  - procedural
  - systemd
---

# Timed `systemd` units

In order to use [systemd](./systemd.md) in the manner of [cron](./Cron.md) (but
with added benefits, such as being able to set the user to run as, environment
variables and so on), you first create a timer template, e.g.:

```
# everyhour@.timer
[Unit]
Description=Run %i every hour

[Timer]
OnCalendar=*-*-* *:00:00
Persistent=true
Unit=%i.service

[Install]
WantedBy=timers.target
```

You can then pass in specific units using this template to `systemctl`.

As an example, this unit runs a simple bash script that pings a server:

```
# ping-eolas-api.service

[Unit]
Description=Ping Eolas API to check it is up

[Service]
User=thomas
Group=thomas
Type=oneshot
ExecStart=/home/thomas/self-host/scripts/ping_eolas-api.sh
```

Then when enabling the service, do the usual:

```sh
systemctl daemon-reload
```

But when enabling/starting, invoke the timer template, viz:

```sh
systemctl enable everyhour@ping-eolas-api.timer
systemctl start everyhour@ping-eolas-api.timer
```

The schema is:

```
[timer_template_name][service_name].template
```