How to prevent rsyslog from logging cron tasks to /var/log/syslog using additional config

Question

I have a Docker image for cron tasks. Here is the Dockerfile:

FROM php:8.0-fpm

RUN apt-get update
RUN apt-get install -y cron rsyslog

RUN touch /var/log/cron.log
RUN chmod 0777 /var/log/cron.log

COPY ./app /var/www/app
COPY crontab /etc/cron.d/crontab
RUN chmod 0644 /etc/cron.d/crontab
RUN crontab /etc/cron.d/crontab

COPY 02-cron.conf /etc/rsyslog.d/02-cron.conf

CMD service rsyslog start && service cron start && tail -f /dev/null

By default rsyslog logs cron to /var/log/syslog. I want to log cron to a separate file /var/log/cron.log.

rsyslog's master config /etc/rsyslog.conf has the following lines:

*.*;auth,authpriv.none      -/var/log/syslog
#cron.*             /var/log/cron.log

I want to disable logging cron to /var/log/syslog and enable logging it to /var/log/cron.log by adding one more config /etc/rsyslog.d/02-cron.conf:

*.*;cron,auth,authpriv.none     -/var/log/syslog
cron.*                          /var/log/cron.log

But the result is that cron logs to both /var/log/syslog and /var/log/cron.log.

Answer 1

Line in you config:

*.*;cron,auth,authpriv.none     -/var/log/syslog

make it like this:

*.*;cron.none,auth,authpriv.none     -/var/log/syslog

to stop cron from logging in syslog

And also you can add dash (-) in front of the path for cron log to avoid flush of buffers on every write. So your cron line to become:

cron.*                          -/var/log/cron.log