The ability to perform a certain task at a specific time or at regular intervals is a necessary task for sys admins. The original cron daemon offers an easy method for job scheduling on Unix-based systems. Although cron has seen a number of improvements over the years, even the newer versions are designed for very basic scheduling. An administrator who wants to do anything unusual must either create a wrapper script or build the additional functionality into whatever script is started by cron.

Imagine how much time you could save if you no longer needed to create wrappers, hack your scripts, or do anything else to get programs to react to error conditions and run at exactly the time you need – in exactly the order they should. Several commercial products offer this functionality, but they can take a big bite out of your IT budget. Luckily, the open source world also provides solutions for beyond-cron scheduling.

In this article, I will explain how to get started with a powerful alternative: the Open Source Job Scheduler.With any scheduling software, the primary administrative unit is the job, which is typically a script or program started by the scheduling software. In many cases, cron is sufficient to handle the most simplistic scheduling requirements, such as running a certain job once a day (i.e., backups). Even jobs that need to run at more frequent intervals (every 15 minutes), less frequently (once a month), or even on specific dates (the first of the month) can be handled by cron.

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