DilOS platformHow to setup cron

How to setup cron

Cron is a clock daemon which allows you to start a job at specified date (and/or time) or every specified time period.

Firstly you need to install a package, do it as root:

installing of the package
root@dilos:~# apt-get update && apt-get install cron

After it the package should be installed in your system, let check it:

checking of the package
root@dilos:~# dpkg -l cron
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                          Version             Architecture        Description
ii  cron                          3.0pl1-128-5        solaris-i386        process scheduling daemon

The output means that the package has been installed.

To know what our daemon does (run the jobs) we need to add one line into the syslog configuration.

Open /etc/syslog.conf in your favorite text editor and add the line (as root):

a line to log from the cron daemon
cron.info   /var/adm/messages

You can write it into a separated file, for example, cron.log.

After you changed syslog.conf you need to reconfigure syslog daemon (as root):

reconfiguring of the syslog daemon
root@dilos:~# svcadm refresh system-log

Refresh method sends a HUP signal to the syslogd and the daemon will reread its configuration file.

Now we need to enable the service (as root):

enabling of the cron service
root@dilos:~# svcadm enable cron

Let check the status of the service:

checking status of the service
root@dilos:~# svcs cron
STATE          STIME    FMRI
online         10:09:20 svc:/system/cron:default

The state must be online, this means that the service works now.

From time to time you need to debug some jobs that cron runs, to increase a log level of the cron daemon you need to change service info (by default log level is 1).

To change this value run (as root):

changing os the log level
root@dilos:~# svccfg -s cron setprop application/log_level = astring: 15

To be sure the value changed you can test it:

examining value of the log_level
root@dilos:~# svcprop -p application/log_level cron

Don't forget to refresh the service after changes (as root):

refreshing the service
root@dilos:~# svccfg -s svc:/system/cron:default refresh
root@dilos:~# svcadm refresh cron

And now you can restart the daemon (as root):

restarting the service
root@dilos:~# svcadm disable cron
root@dilos:~# svcadm enable cron

Always check the result of this operation, otherwise your service may be unavailable.

checking of the result
root@dilos:~# svcs -xv
root@dilos:~# ps -ef|grep cron
    root  4574     1   0 19:37:39 ?           0:00 /usr/sbin/cron -L 15
    root  4577  4556   0 19:37:47 pts/1       0:00 grep cron

Well, done...

log level codes

  • 1 job start
  • 2 job end
  • 4 job failed
  • 8 job pid

You can combine this codes by OR (or +), in our example we set all of them (1 + 2 + 4 + 8 = 15)