RHCE # Week # 277


Fill in the blanks

The _________ service is designed to cron jobs that could not run while a server was powered down.


Anacron is a computer program that performs periodic command scheduling which is traditionally done by cron, but without assuming that the system is running continuously. When executed, Anacron reads a list of jobs from a configuration file, normally /etc/anacrontab. This file contains the list of jobs that Anacron controls. Each job entry specifies a period in days, a delay in minuts, a unique job identifier, and a shell command.

For each job, Anacron checks whether this job has been executed in the last n days, where n is the period specified for that job. If not,Anacron runs the job's shell command, after waiting for the number of minutes specified as the delay parameter.

After the command exits, Anacron records the date in a special timestamp file for that job, so it can know when to execute it again. Only the date is used for the time calculations. The hour is not used.

fcron is another implementation of cron which attempts to fulfill the roles of both Vixiecron and anacron.

fcron is a periodical command scheduler which aims at replacing Vixie Cron, so it implements most of its functionality.

But fcron does not assume that your system is running either all the time nor regularly : we can, for instance, tell fcron to execute tasks every x hours y minutes of system up time or to do a job only once in a specified interval of time.

fcron should be started from /etc/rc or /etc/rc.local

Answer:  Anacron / fcron