Systemd

Show all running services
systemctl list-units --type=service

Creation of a failsafe service

[Unit]

Description=My App
StartLimitIntervalSec=30
StartLimitBurst=2

[Service]
ExecStart=/usr/local/sbin/my-app.sh
Restart=on-failure

The StartLimitBurst=2 and StartLimitIntervalSec=30 settings tell systemd that if the service unsuccessfully tries to restart itself twice within 30 seconds, it should enter a failed state and no longer try to restart.
hard iron in Service:
Restart=always
RestartSec=10 (or more seconds)

Delay a service:

[Service]
ExecStartPre=/bin/sleep 30

Build a timer that runs a script
/etc/systemd/system/foo.timer

[Unit]
Description=Daily autoboot

[Timer]
OnCalendar=*-*-* 06:30:00
Persistent=true

[Install]
WantedBy=timers.target

/etc/systemd/system/foo.service

[Unit]
Description="Reboot device"

[Service]
Type=simple
ExecStart=/usr/bin/systemctl --force reboot

Update changes

systemctl daemon-reload