systemd -

Timers

Debug commands for timers.

systemctl --all                   # list all systemd "units"
systemctl list-timers             # list all systemd timers
systemctl start cleanup.timer     # start a specific timer

/files/cleanup.service

[Unit]                  # section defines service metadata
Description=Cleanup     # human-readable name
After=network.target    # when will the service be started

[Service]                   # defines configuration for services
Type=oneshot                # one-off task, manager will wait for this to finish
ExecStart=/bin/echo hello   # what to run

[Install]                   # section defines behavior when enabled
WantedBy=multi-user.target  # start when the target (multi-user runlevel) starts

files/cleanup.timer

[Unit]                      # section defines service metadata
Description=Cleanup Timer   # human-readable name

[Timer]             # defines configuration for timers
OnCalendar=*:0/15   # ran every 15 minutes
Persistent=true     # ran immediately if should've ran when timer was inactive

[Install]               # section defines behavior when enabled
WantedBy=timers.target  # start when the target (timer manager) starts

tasks/install-server.yml, example Ansible setup.

# ...

- name: copy cleanup job file
  become: true
  copy:
    src: ../files/cleanup.service
    dest: /etc/systemd/system/cleanup.service

- name: copy cleanup timer file
  become: true
  copy:
    src: ../files/cleanup.timer
    dest: /etc/systemd/system/cleanup.timer

- name: enable cleaning service
  become: true
  systemd:
    name: cleanup.timer
    state: started
    enabled: true