Prevent forwarding of systemd service logs to syslog without affecting other service logs sent to syslog

user_8215209 0
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My computer runs serveral java processes as systemd services.The systemd logs get accumulated in the syslog eventually leading to low disk space . How to re-direct the logs started by systemd services towards /dev/null so that it does not accumulate in syslog.The machine is constantly running out of disk space due to this issue.However , I need to be able to use journalctl to view the systemd service logs. The possible solutions I found were :

1.To modify configurations in /etc/systemd/journald.conf by setting 'ForwardToSyslog=no'

2.Adding StandardOutput=null within the systemd service file itself

However the first solution completely stopped all the logs sent to syslog and solution 2 did not work.I wish to stop forwarding only the log messages from systemd services.

systemd syslog ubuntu logging linux
3 Answers

The second option with StandardOutput=null should work. I think what you need is to redirect also STDERR to /dev/null, by adding StandardError=null. Summarize - in your *.service file should be two lines:

[Service]
StandardOutput=null
StandardError=null

Refer SYSTEMD.EXEC(5) man page for more details.

user_69065090

Similarly on a Redhat 7.4 box, running systemd-219-42.el7_4.1.x86_64, I was unable to turn off log redirection with the 'ForwardToSyslog=no' setting in /etc/systemd/journald.conf.

I instead had success with setting 'MaxLevelSyslog=warning' which removed all the INFO and DEBUG level messages that were being forwarded to rsyslog.

user_6338190

You can configure rsyslog to ignore logs from specific application:

# cat /etc/rsyslog.d/mydaemon.conf 
if $programname == 'mydaemon' then {
    stop
}

This will result in:

  1. You will see systemd-generated messages about daemon being started/stopped/reloaded/etc within journal AND syslog.
  2. You will see daemon's-generated messages ONLY in journal (and custom log file written directly by application, if any).
user_5424520
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