We’ll follow the documentation from here.

Changes are made to the /etc/rsyslog.conf config file.

For this example, we will be configuring our named.log file to not exceed 50MiB, and then we’ll have a rotated log “.1” that is also 50MiB. Total it should not exceed 100BMiB.

First we need to create an out channel, and then we assign the out channel to a logging channel. We also need a script that rotates the logs.

Create the Output Channel

$outchannel log_rotation,/var/log/named.log, 52428800,/home/user/log_rotation.sh

Assign Output Channel to Logging Channel

On our line that is logging named, at the end add :$log_rotation

Example:

local0.*                   /var/log/named.log:$log_rotation

Script to Rotate Log

Somewhere on the system, create a rotate.sh script. Name it whatever you want, just be sure the path and name in the rsyslog.conf is the same.

Add the following one line to move the current log to a rotate log.

mv -f /var/log/named.log /var/log/named.log.1

As the log fills up and hits ~50MiB, the named.sh script will run which rotates(moves) the log file to logfile.log.1. This will keep our usage for named.log to 100MiB.