Ubuntu – How to change cron log level

cronlogservicessystemdupstart

I replaced exec cron with exec cron -L 15 the run sudo service cron reload, sudo service cron restart but nothing changed. Cron doesn't log the end of jobs and doesn't log failed jobs. I hade no problem in Ubuntu 14.04, but now I have this problem in Ubuntu 16.04. What do I do wrong?

Step by Step:
First I changed /etc/init/cron.conf:

sudo sed -i 's|exec cron$|exec cron -L15|' /etc/init/cron.conf && sudo restart cron && cat /etc/init/cron.conf

So now it is 

$ cat /etc/init/cron.conf
# cron - regular background program processing daemon
#
# cron is a standard UNIX program that runs user-specified programs at
# periodic scheduled times

description "regular background program processing daemon"

start on runlevel [2345]
stop on runlevel [!2345]

expect fork
respawn

exec cron -L 15

I made the same config in my Ubuntu 16.04 as well as on Ubuntu 14.04 on the another PC.

The Cron log in Ubuntu 14.04 is the following:

$  grep CRON /var/log/syslog
Aug 26 16:05:01 y1404 CRON[6825]: (y) CMD (foo # JOB_ID_1)
Aug 26 16:05:01 y1404 CRON[6824]: (CRON) error (grandchild #6825 failed with exit status 127)

So you can see the second line with error notification about nonexistent command foo. But in Ubuntu 16.04 there is no error notification in the log:

Aug 26 16:25:01 my CRON[7259]: (y) CMD (foo # JOB_ID_129)

Best Answer

From Ubuntu 15.04 on, upstart using /etc/init/*.conf is replaced by systemd using configuration files in /lib/systemd/system/ and /etc/systemd/system/. Although a file /etc/init/cron.conf is still existent in Ubuntu 16.04, the script normally in use to start cron now is /lib/systemd/system/cron.service. If you want to add extra options, edit this file with

sudo systemctl edit --full cron

and replace the line

ExecStart=/usr/sbin/cron -f $EXTRA_OPTS

by e. g.

ExecStart=/usr/sbin/cron -L 15 -f $EXTRA_OPTS

To reload the configuration, run sudo systemctl restart cron or just reboot. You can test what exact command a service was started with using systemctl status, e. g. for cron (see last line):

> systemctl status cron
● cron.service - Regular background program processing daemon
   Loaded: loaded (/lib/systemd/system/cron.service; enabled; vendor preset: enabled)
   Active: active (running) since So 2017-08-27 09:56:18 CEST; 1h 15min ago
     Docs: man:cron(8)
 Main PID: 26021 (cron)
   CGroup: /system.slice/cron.service
           └─26021 /usr/sbin/cron -f
Related Question