Also, SOS does not market their product – or even their services – in the traditional sense. Note that the product is the same with both licenses.Īlthough some products provide more features in the commercial version, SOS Managing Director Andreas Püschel sees their business focused on support and service and not the product itself. Both license types provide the same basics, including all of the functionality, source code, and upgrades. It also supports several different databases, including DB2, Oracle, MS SQL Server, PostgresSQL, and MySQL.ĭepending on your needs, two different licenses are available: GPL and Guaranteed License. Versions are available for Linux, Solaris, HP-UX (PA-RISC, IA64), AIX, and Windows. One amazing solution is the Open Source Job Scheduler, developed by Software- und Organisations-Service (SOS) GmbH in Berlin, Germany. Problems with job scheduling and commercial software licensing have not gone unnoticed by the open source community. Commercial products can cost a small fortune and are often licensed on the basis of the number of servers or, in some cases, the number of scripts you start. The limitations of cron have not gone unnoticed, and a number of products have come on the market. Cron was a useful tool in its time, and often still is, but the requirements of many companies rule it out. For example, some Unix dialects do not support a central /etc/crontab file, so you need to set up files for individual users. Rabbit to the RescueĪlthough you can install open source versions of cron on Windows machines, dealing with different operating systems causes even more problems. To distribute crontabs to these remote machines, you could configure rsync or use some other mechanism, but this quickly becomes an administrative nightmare when the configuration is different across several machines, when jobs need to be started manually often, and when other tasks exist that are not part of cron's functionality. Many tasks need to be managed on multiple machines, so the better scheduling software allows you to manage all of your machines from a central point, remotely start jobs, and so forth. Naturally, on many occasions, specific jobs must be started on demand rather than waiting for a specific event. Often jobs simply wait until either a specific file is delivered or anything at all arrives in a predefined directory. Even the newest versions of cron cannot handle this, especially if you need to be able jump into the middle of the chain occasionally and start a job from there.Įvents that start jobs can be more than just specific times or the completion of other jobs. If one step fails, the execution of subsequent jobs would create major problems. In my work, I have a number of job chains that consist of up to a dozen individual jobs that must be run in a precise order, and each job can only run if the previous job in the chain was successful. When you start dealing with dependencies of any kind, you quickly begin to see the limitations of cron – for example, if you want to start a specific program after a certain event occurs. 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. 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). 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. Luckily, the open source world also provides solutions for beyond-cron scheduling. Several commercial products offer this functionality, but they can take a big bite out of your IT budget. 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. 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. Although cron has seen a number of improvements over the years, even the newer versions are designed for very basic scheduling. The original cron daemon offers an easy method for job scheduling on Unix-based systems. The ability to perform a certain task at a specific time or at regular intervals is a necessary task for sys admins.
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