Stop rtkit-daemon from spamming logs with "Supervising X threads of Y processes of Z users"

Question

journalctl -b | grep Supervising | wc -l
2819

Distro is Fedora 35, vanilla, with PipeWire running the show.

I'm pretty sure all modern Linux distros are affected but people don't care.

There's no rsyslog here and journald doesn't support filtering.

This is getting ridiculous. I can patch it for sure but the question is how it can be done without applying patches and rebuilding. The thing, /usr/libexec/rtkit-daemon, doesn't even have a man page and nothing in its --help offers any clues.

There's a related question which has never been answered as well: rtkit: list threads it is "supervising"?

I can only think of running rtkit-daemon through some wrapper which simply disables all the features related to /dev/log/system logging. Has anyone seen anything like that?

I've filed a bug report just in case.

Answer 1

As Artem rightly wrote, the systemd journal has very limited filtering capabilities. Hence the only solution to limit services or desktop applications verbosity is to organize the filtering earlier in the logging pipeline, before any further processing of any sort.

In order to achieve this for a systemd service :

A/ Locate the directory associated with the service you want to tune. Usually based in (/usr)/lib/systemd/system for services distributed at package's install time such as rtkit-daemon. In this particular case : rtkit-daemon.service.d

B/ Within this directory, (or better in a system-wide configuration subdir /etc/systemd/system/rtkit-daemon.service.d since it won't then be silently removed by further package upgrades) edit or create a log.conf file in order to insert the following statements :

[Service]
LogLevelMax=X

With X standing for the desired numeric loglevel or its associated alphabetical symbol taken from the following list :

• 0 or emergency, (highest priority messages)
• 1 or alert,
• 2 or critical,
• 3 or error,
• 4 or warning,
• 5 or notice,
• 6 or info
• 7 or debuginfo (lowest priority messages)

For a given level chosen, logs of all higher levels won't be output. Note that if no loglevel is specified in whatever systemd service .conf file, the loglevel of the daemon defaults to 7, in other words allowing the highest level of verbosity.

Regarding your specific need as worded in the title, LogLevelMax=5 (notice) should suffice (6 as reported in comments).

C/ Save and exit your editor then run the two following commands :

systemctl daemon-reload
systemctl restart rtkit-daemon.service

---

Nota Bene : Since "New style daemons" (sic)��� will be executed in their own session, with standard input connected to /dev/null and standard output/error connected to the systemd-journald.service(8) logging service logging can be achieved via whatever simple (f)print(f). It can then be possible to completely silence the daemon by simply redirecting its stdout and stderr to /dev/null.

While I easily imagine this is not recommended (since wiseness would command to let at least critical errors have their way to syslog), this redirection can be achieved via the following statements :

[Service]
StandardOutput=null
StandardError=null

Credits : Answer based on systemd.exec documentation