printk

printk on wikipedia.

For years I was really annoyed, that the kernel logs were printed to the console of a linux server.

Logging firewall drops sometimes completely swamped the console, making it difficult to type.

Turns out the logging to console can be turned down really easily, by configuring printk.

Configure printk to be less annoying

So first of check the current printk settings:

cat /proc/sys/kernel/printk

It will output something like:

4	4	1	7

Which translates to:

	console_loglevel	default_message_loglevel	minimum_console_loglevel	default_console_loglevel
0 - emergency	x			x
1 - alert	x		x	x
2 - critical	x			x
3 - error	x			x
4 - warning	x	x		x
5 - notice				x
6 - informational				x
7 - debug				x

From: Runtime configuring printk – stop kernel printk from flooding the console

And the default console loglevel of 7 is way too loud. And normally the advice online is to set it to 3.

Or rather to set it to 7 4 1 3.

This most commonly done by editing /etc/sysctl.conf and uncomment the following:

# Uncomment the following to stop low-level messages on console
# kernel.printk = 3 4 1 3

Some distros (Debian Trixie) doesn’t include a /etc/sysctl.conf, but then add a file like /etc/sysctl.d/my.conf with the line kernel.printk = 3 4 1 3.