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

[Silvio Knizek]

Am Mittwoch, den 06.05.2020, 11:21 +0200 schrieb 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

Hi Ulrich,

as you quoted right --kill-who takes either "main", "control" or "all",
not a PID.

BR
Silvio