• 0 = emergency
• 1 = alert
• 2 = critical
• 3 = error
• 4 = warning
• 5 = notice
• 6 = info & debug

Exemple :

[Service]
LogLevelMax=3

[Unit]
After=hibernate.target
After=hybrid-sleep.target
After=suspend.target
After=suspend-then-hibernate.target
 
[Service]
Type=simple
ExecStart=/bin/systemctl --no-block restart your-unit.service

[Install]
WantedBy=hibernate.target
WantedBy=hybrid-sleep.target
WantedBy=suspend.target
WantedBy=suspend-then-hibernate.target

• https://systemd.io/
• https://fr.wikipedia.org/wiki/Systemd