I'd like to prevent the kernel and systemd from logging boot (service) status messages to a tty.
Example output from a Debian Stretch/8 VM:
The systemd man page talks about some parameters supposely controlling the logging:
- The systemd kernel parameter
systemd.show_status - The kernel kernel parameter
quiet, also examined by system
From the man page:
systemd.show_status=
Takes a boolean argument or the constant auto. If yes, the systemd manager (PID 1) shows terse service status updates on the console during bootup. auto behaves like false until a service fails or there is a significant delay in boot. Defaults to yes, unless quiet is passed as kernel command line option, in which case it defaults to auto.
(Emphasis mine.)
In my opinion the opposite from what I've highlighted is exactly what I want - though it does not work.
I unsuccessfully tried the kernel parameters
# the man page was unclear whether false, 0 or no is correct
systemd.show_status=false
systemd.show_status=0
systemd.show_status=no
# the man page says the above config defaults to the value of the kernel parameter "quiet"
quiet
# log "less"
systemd.log_level=err
# explicitly say where to log to
systemd.log_target=journal-or-kmsg
# explicitly say where to log/output to even though the default should be "journal"
systemd.default_standard_output=journal
They have no effect - I still see the status messages.
(I added the last three options in desperation and to rule out other error sources.)
The command line is
$ cat /proc/cmdline
... quiet systemd.show_status=false systemd.log_level=err systemd.log_target=journal-or-kmsg systemd.default_standard_output=journal
Systemd version is 232-7, the OS is a late 2016 Raspbian (Debian 7 based) with some packages, including sytemd partially upgraded to Debian Stretch/8:
Linux raspberrypi 4.4.38-v7+ #938 SMP Thu Dec 15 15:22:21 GMT 2016 armv7l GNU/Linux
However on a fresh Debian Stretch/8 with the same systemd version and apparently the same configuration and only a quiet option I don't see the logging at all. On that fresh system specifying systemd.show_status=yes leads exactly to the behavior I want to get rid of on the other system.
- Should the kernel option mentioned at the beginning actually work on its own as expected?
- How can I identify what's logging to the console?
