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4.13. Cron

Vixie cron and Cronie
Red Hat Enterprise Linux 6 includes the cronie package as a replacement for vixie-cron. The main difference between these packages is how the regular jobs (daily, weekly, monthly) are done. Cronie uses the /etc/anacrontab file, which by default looks like the following:
# the maximal random delay added to the base delay of the jobs

# the jobs will be started during the following hours only

# period in days   delay in minutes   job-identifier                    command

1                       5               cron.daily      nice run-parts  /etc/cron.daily
7                       25              cron.weekly     nice run-parts  /etc/cron.weekly
@monthly                45              cron.monthly    nice run-parts  /etc/cron.monthly
These regular jobs will be executed once a day in the 03:00-22:00 time interval, including a random delay. For example, cron.daily will have a 5 minute forced delay plus a random delay of 0-45 minutes. You could also run jobs with no delays, between 4 and 5:
RANDOM_DELAY=0 # or don't use this option at all


# period in days   delay in minutes   job-identifier                    command
1                       0               cron.daily      nice run-parts  /etc/cron.daily
7                       0               cron.weekly     nice run-parts  /etc/cron.weekly
@monthly                0               cron.monthly    nice run-parts  /etc/cron.monthly
Features of cronie include:
  • Random delay for starting the job in /etc/anacrontab.
  • Time range of regular jobs can be defined in /etc/anacrontab.
  • Each cron table can have its own defined time zone with the CRON_TZ variable.
  • By default, the cron daemon checks for changes in tables with inotify.
For further details about cronie and cronie-anacron, please refer to the Red Hat Enterprise Linux Deployment Guide.

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