[systemd-devel] Q: systemctl kill: "Invalid who argument 15862"

[Ulrich Windl]

Hi!

I have a question for systemd-228-150.82.1.x86_64 (of SLES12 SP4):
While developing a script for logrotate, I tested this command with the
following result:

# systemctl kill -s HUP --kill-who=15862 iotwatch at LOC1.service 
Failed to kill unit iotwatch at LOC1.service: Invalid who argument 15862

That's odd, because:
# systemctl status iotwatch at LOC1
● iotwatch at LOC1.service - iotwatch I/O performance monitor instance "LOC1"
   Loaded: loaded (/etc/iotwatch.conf; enabled; vendor preset: disabled)
   Active: active (running) since Tue 2020-03-10 07:58:35 CET; 1 months 26
days ago
     Docs: man:iotwatch(1)
           man:iotwatch at .service(8)
 Main PID: 15862 (iotwatch-LOC1)
    Tasks: 4 (limit: 512)
   CGroup: /system.slice/system-iotwatch.slice/iotwatch at LOC1.service 
           └─15862 iotwatch-LOC1 -l /var/log/iotwatch/LOC1/iotwatch-LOC1.log
...

Mar 10 07:58:35 rksapv04 systemd[1]: Starting iotwatch I/O performance
moni.....
Mar 10 07:58:35 rksapv04 systemd[1]: Started iotwatch I/O performance
monit...".
Hint: Some lines were ellipsized, use -l to show in full.


Did I misinterpret the manual page, or what is the problem?

       --kill-who=
           When used with kill, choose which processes to send a signal to.
           Must be one of main, control or all to select whether to kill only
           the main process, the control process or all processes of the
unit.

Regards,
Ulrich