Systemd units
Service units
Start service manually:
systemctl --user start daily.service
systemctl --user status daily.service
User units:
systemctl --user status
systemctl status user@1000 -l
List units
List all failed user services:
systemctl --user --no-legend --state=failed --plain list-units
Instance units from template files
- Remove failed and wrong instance units
systemctl reset-failed
Service dependencies
To see the dependency tree of a unit (which units systemd will attempt to activate when starting the unit):
systemctl list-dependencies NetworkManager-wait-online.service
This will show the dependent units, with target units recursively expanded. To expand all dependent units recursively, pass the --all flag:
systemctl list-dependencies --all NetworkManager-wait-online.service
To show the reverse dependency, i.e. which service depends on NetworkManager-wait-online.service:
systemctl list-dependencies --reverse NetworkManager-wait-online.service
Service watchdog
https://www.medo64.com/2019/01/systemd-watchdog-for-any-service
Timers
cd ~/.config/systemd/user
vi test.timer
vi test.service
systemctl --user enable test.timer
systemctl --user start test.timer
systemctl --user list-timers
Changing user timers/services
systemctl --user daemon-reload
Time formats
man systemd.time
Unit overrides/drop-ins
Show all overrides system-wide:
systemd-delta --type=extended
Show concatenated unit propoerties:
systemctl cat autorandr
systemctl show autorandr
Add override/drop-in
Using systemctl edit
Use systemctl edit to automatically create a drop-in file:
systemctl edit libvirtd.service
Then add i.e.
[Unit]
After=network-online.target
This will create /etc/systemd/system/libvirtd.service.d/override.conf)
with the same content, and reloads the systemd daemon to activate the changes.
Manually
Using the example of https://github.com/prometheus-community/node-exporter-textfile-collector-scripts/issues/97#issuecomment-851957644
cd /etc/systemd/system
mkdir prometheus-node-exporter-smartmon.service.d
echo -e '[Service]\nEnvironment=LC_NUMERIC=C' > prometheus-node-exporter-smartmon.service.d/lc_numeric.conf
systemctl daemon-reload
systemctl status prometheus-node-exporter-smartmon
systemctl restart prometheus-node-exporter-smartmon
Debug failing unit
systemctl list-units --failed
Start service when there's an actual network connection
Unfortunatly all targets seems to be very static, I can't figure out how to do this dynamically on a Laptop with ever changing connectivity.
Remove systemd services
systemctl stop [servicename]
systemctl disable [servicename]
rm /etc/systemd/system/[servicename]
rm /etc/systemd/system/[servicename] # and symlinks that might be related
rm /usr/lib/systemd/system/[servicename]
rm /usr/lib/systemd/system/[servicename] # and symlinks that might be related
systemctl daemon-reload
systemctl reset-failed