Re: Crontab | random execution time

On Mon, 7 Mar 2022 14:36:19 +0100
Jos Chrispijn <bsduser@cloudzeeland.nl> wrote:

> Dear list,
> I am trying to run a cron job, starting once every two hours and at 
> random minute  in the half our of that cron scheme:
> 
> SHELL=/bin/sh
> PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:/usr/local/etc
> 0~30   */2     *       *       *       root /root/cronjobs/run_myjob
> 
> Unfortunately it is running exactly on the hour instead of random 
> between 0-30 minutes.

	I'd expect that to run once a minute for the first thirty minutes
of even numbered hours.

	The usual way to achieve what you want is to add a random sleep in
front of the job, or just rely on cron's jitter feature which isn't usually
set for that much spread and affects every job.

-- 
Steve O'Hara-Smith <steve@sohara.org>