64 lines
1.5 KiB
Markdown
64 lines
1.5 KiB
Markdown
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# Systemd Timers
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Gen Z's crontab
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Generally there are 3 pieces to a timer
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- The script being run
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- The systemd service defining which script to run
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- The systemd timer triggering the service
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## Tools
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`systemd-analyze calendar` can be very handy at verifying timestamps
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```bash
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systemd-analyze calendar *-*-* *:10,20:10
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```
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To find suitable targets for things like `Wants` and `After`, see
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`systemd.special(7)`. If you want to check the current status of your targets,
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use:
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```bash
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systemctl list-units --type target --state active
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systemctl status network-online.target
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```
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## Placing files
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Scripts should be put in `/usr/local/bin` if they can be run by anyone or
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`/usr/local/sbin` if they should only be run by root
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Define a `xxx.service` file in `/etc/systemd/system`. Set the timer as one of
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its `Wants`. `network.target` may be more appropriate in some cases.
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`multi-user.target` is a good default for `WantedBy`
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```systemd
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[Unit]
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Description = Sends current ip address to uni servers
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Wants = broadcast_ip.timer
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Wants = network.target
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After = network.target
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[Service]
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Type = oneshot
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ExecStart = /usr/local/bin/broadcast_ip.sh
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[Install]
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WantedBy = multi-user.target
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```
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Now you'll need a timer file. It's easiest to make it have the same name as the
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service file and put it in the same `/etc/systemd/system`
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```systemd
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[Unit]
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Description = Sends current ip address to uni servers
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Requires = broadcast_ip.service
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[Timer]
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Unit = broadcast_ip.service
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OnCalendar = *-*-* *:15,45:00
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[Install]
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WantedBy = timers.target
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```
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