shell-things/etc/systemd/system/sysctl-p--system.service

[Unit]
Description=Read /etc/sysctl.conf and /etc/sysctl.d/

[Service]
Type=oneshot
TimeoutStartSec=infinity
ExecStart=-/usr/sbin/sysctl -p --system
User=root
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target