How to create a debug log — rsyslog 8.2502.0 documentation

# How to create a debug log

Creating a debug log is actually quite simple. You just have to add a few lines to the configuration file.

## Regular debug output

Add the following right at the beginning of the rsyslog.conf file. This will ensure that debug support is the first thing to enable when the rsyslog service is started:

    $DebugFile /var/log/rsyslog.debug
    $DebugLevel 2

The actual file path and name may be changed if required.

Having set the above, when rsyslog is restarted it will produce a continuous debug file.

## Debug on Demand

For having rsyslog be ready to create a debug log (aka Debug on Demand), the settings are a little different.

    $DebugFile /var/log/rsyslog.debug
    $DebugLevel 1

Now, rsyslog will not create a debug log on restart, but wait for a USR signal to the pid. When sent, the debug output will be triggered. When sent again, debug output will be stopped.

    kill -USR1 `cat /var/run/rsyslogd.pid`

## Notes

- Having debug output enabled, the debug file will grow very quickly. Make sure to not have it enabled permanently. The file will eventually fill up the disk.

- Debug mode is not to be used in a productive environment as a permanent setting. It will affect the processing and performance.

## See Also

- Troubleshooting doc page.

- Debug Support doc page with more detailed information.

See also

Help with configuring/using `Rsyslog`:

- Mailing list - best route for general questions

- GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with `Rsyslog`

See also

Contributing to `Rsyslog`:

- Source project: rsyslog project README.

- Documentation: rsyslog-doc project README

Copyright 2008-2023 Rainer Gerhards (Großrinderfeld), and Others.