Installing a Cron Daemon

Revision as of 23:46, 10 January 2014 by Duncan.Britton (Talk)

Introduction

Cron daemons allow you to configure certain tasks to be run at specific times. Installing a cron daemon is a good idea because some packages may assume that you have a cron daemon installed and create jobs to update their databases with a cron daemon. There are several different loggers available to Funtoo users:

Installation

To install the cron daemon of your choice, run the following command:

# emerge --ask fcron

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N     ] sys-process/cronbase-0.3.2-r1
[ebuild  N     ] sys-process/fcron-3.1.2-r2  USE="mta pam readline system-crontab -debug (-selinux)" LINGUAS="-fr" 

Would you like to merge these packages? [Yes/No] yes

Now enable the cron init script so that is starts when your system boots, and enable the cron daemon:

# rc-update add fcron default
 * service fcron added to runlevel default
# rc
 * Caching service dependencies ...              [ ok ]
 * Starting fcron ...                            [ ok ]

System Cron Jobs

After the cron daemon has been emerged, you may see a message to run emerge --config to configure your cron daemon to process system cron jobs. System cron jobs are scripts that are installed by various packages into the following directories:

  • /etc/cron.hourly
  • /etc/cron.daily
  • /etc/cron.weekly
  • /etc/cron.monthly

For example, you should find a /etc/cron.daily/man-db script that is installed by the sys-apps/man-db ebuild. This system cron job's purpose is to update the man cache every day, and it will run only if you enable your cron daemon to manage system cron jobs.

You may choose to enable your cron daemon so that it runs system cron jobs, or choose not to. Enabling a cron daemon to run system cron jobs will result in a bit more disk and CPU activity on your system, but should ensure that the system runs more optimally most of the time (proper caching of man pages, etc.) It is recommended for most systems, but your system will still function without system cron jobs active.

If you would like to have your system run system cron jobs, use emerge --config as specified in the emerge output:

# emerge --config sys-process/fcron
Configuring pkg...

 * This is going to set up fcron to execute check_system_crontabs.
 * In this configuration, you're no longer free to edit the systab
 * at your leisure, as it'll be rewritten the moment the crontabs
 * are modified.

Rebuilding fcron systab.2013-10-19 21:20:38  
INFO installing file /tmp/fcrontab.84pova for user systab
Modifications will be taken into account right now.

Your cron daemon is now configured to automatically run system cron jobs.