Systemd introduces the concept of systemd units. Units are represented by configuration files located in one of the following directories:
- /usr/lib/systemd/system/ – units from installed RPM packages.
- /run/systemd/system/ – units created at runtime. This directory takes precedence over the directory containing units installed from packages.
- /etc/systemd/system/ – units created and managed by the system administrator. This directory takes precedence over the directory containing units created at runtime.
Create our service file:
# touch /etc/systemd/system/routing-settings.service # chmod 664 /etc/systemd/system/routing-settings.service
with the following content:
[Unit] Description=Routing Settings Service After=network.target
[Service]
Type=oneshot
User=root
ExecStart=/root/routing.sh
[Install]
WantedBy=multi-user.target
User=root – runs as root! Specify (or do not specify) the user under which your script should run. My script must run as root. I cannot say that I am happy about this, as it requires strict control over the script's location and its access permissions.
Type=oneshot means that the process will complete before further units are started. This is quite suitable for scripts.
Check it:
# systemctl start routing-settings
If, after executing the script, we see the expected result, then enable this "service" for autostart:
# systemctl enable routing-settings
Try rebooting. It should work.
Let's see when our service was started:
# systemctl status routing-settings