[systemd-devel] Antw: [EXT] Re: [systemd‑devel] systemctl log verbosity

[Ulrich Windl]

>>> Michael Chapman <mike at very.puzzling.org> schrieb am 17.08.2021 um 02:52 in
Nachricht <885331af-bb7-41d0-e8-26c92023bb77 at very.puzzling.org>:
> On Tue, 17 Aug 2021, Dave Close wrote:
>> I'm trying to run "systemctl show" in a cron script. It works but I get
>> a huge number of extra lines in my log for each run. Why? Can this be
>> suppressed. I don't want to overfill the log.
>> 
>> There is nothing in the man page (that I noticed) indicating that "show"
>> causes anything to be logged. But here's an example of what I see.
>> 
>> >Aug 16 16:10:01 svcs systemd[1]: Created slice User Slice of UID 0.
>> >Aug 16 16:10:01 svcs systemd[1]: Starting User Runtime Directory 
> /run/user/0...
>> >Aug 16 16:10:01 svcs systemd[1]: Finished User Runtime Directory 
> /run/user/0.
>> >Aug 16 16:10:01 svcs systemd[1]: Starting User Manager for UID 0...
>> >Aug 16 16:10:01 svcs systemd[80491]: Queued start job for default target 
> Main User Target.
>> >Aug 16 16:10:01 svcs systemd[80491]: Created slice User Application
Slice.
>> >Aug 16 16:10:01 svcs systemd[80491]: Condition check resulted in Mark boot

> as successful after the 
>> user session has run 2 minutes being skipped.
>> >Aug 16 16:10:01 svcs systemd[80491]: Started Daily Cleanup of User's 
> Temporary Directories.
>> >Aug 16 16:10:01 svcs systemd[80491]: Reached target Paths.
>> >Aug 16 16:10:01 svcs systemd[80491]: Reached target Timers.
>> >Aug 16 16:10:01 svcs systemd[80491]: Starting D‑Bus User Message Bus
Socket.
>> >Aug 16 16:10:01 svcs systemd[80491]: Condition check resulted in PipeWire

> PulseAudio being skipped.
>> >Aug 16 16:10:01 svcs systemd[80491]: Listening on Multimedia System.
>> >Aug 16 16:10:01 svcs systemd[80491]: Starting Create User's Volatile Files

> and Directories...
>> >Aug 16 16:10:01 svcs systemd[80491]: Finished Create User's Volatile Files

> and Directories.
>> >Aug 16 16:10:01 svcs systemd[80491]: Listening on D‑Bus User Message Bus 
> Socket.
>> >Aug 16 16:10:01 svcs systemd[80491]: Reached target Sockets.
>> >Aug 16 16:10:01 svcs systemd[80491]: Reached target Basic System.
>> >Aug 16 16:10:01 svcs systemd[80491]: Reached target Main User Target.
>> >Aug 16 16:10:01 svcs systemd[80491]: Startup finished in 151ms.
>> >Aug 16 16:10:01 svcs systemd[1]: Started User Manager for UID 0.
>> >Aug 16 16:10:01 svcs systemd[1]: Started Session 72 of User root.
>> >Aug 16 16:10:01 svcs root[80504]: ## logger output from cron script ##
>> >Aug 16 16:10:01 svcs systemd[1]: session‑72.scope: Deactivated
successfully.
>> 
>> I see these additional 23 lines (plus the one‑line script output) every
>> time the script runs. That seems excessively verbose to me.
>> 
>> The system is Fedora 34 x86_64.
> 
> Cron jobs are run with pam_systemd, so they are run within a logind 
> session. If there is no other sessions for root at that time, root's own 
> systemd manager is started when the Cron job launches, and is stopped when 
> the Cron job terminates. All of these log messages are related to this.
> 
> You may instead want to make root a lingering user:
> 
>     loginctl enable‑linger root
> 
> This setting is persistent. You can use disable‑linger at a later time to 
> turn it off if necessary.
> 
> With root configured as a lingering user, its systemd manager remains 
> running all the time.

After reading the manual page I wonder: Is tha tsetting persistent, i.e.:
Where is that setting stored?

Regards,
Ulrich