Systemd kurz und knapp

Listing aller Services

• systemctl --type=service

Logging eines Dienstes

• journalctl -u ssh

Logging eines Dienstes fortlaufend

• journalctl -f -u ssh

Starten eines Service

• systemctl start dienst

Stoppen eines Service

• systemctl stop dienst

Restarten eines Service

• systemctl restart dienst

Aktivieren eines Service

• systemctl enable dienst

Deaktivieren eines Service

• systemctl disable dienst

Status eines Service

• systemctl disable dienst

Anlegen eines Dienstes

Beispiel einer Firewall

• echo '#!/bin/bash' > /usr/local/sbin/firewall
• chmod +x /usr/local/sbin/firewall
• cat /etc/systemd/system/firewall.service

[Unit]
Description=firewall
After=network.target syslog.target

[Service]
RemainAfterExit=yes
ExecStart=/usr/local/sbin/firewall start
ExecStop=/usr/local/sbin/firewall stop
User=root

[Install]
WantedBy=multi-user.target

Aktivieren

• systemctl daemon-reload
• systemctl enable firewall.service
• systemctl start firewall.service

Set Target

• systemctl -f enable multi-user.target
• systemctl -f enable graphical.target

Get Default Target

• systemctl get-default

graphical.target

Changing Target

• systemctl isolate multi-user.target

Set Default Target

• systemctl set-default multi-user.target

Show Targets

• systemctl list-units --type target

UNIT                        LOAD   ACTIVE SUB    DESCRIPTION
basic.target                loaded active active Basic System
bluetooth.target            loaded active active Bluetooth
ceph-mds.target             loaded active active ceph target allowing to start/stop all ceph-mds@.service instances at once
ceph-mon.target             loaded active active ceph target allowing to start/stop all ceph-mon@.service instances at once
...