We use Oozie scheduler in Hue GUI on Hadoop cluster to schedule our Spark workflows. One of the ways to specify schedule is via crontab. The above website translates crontab into “human readable” form. As you can see, it’s very convenient just to try out different expressions and find the time interval you would like a job to run.
In 2015 I wrote a Hadoop cluster server log monitor to capture failed jobs/tasks/attempts into Postgres tables. I used cron to specify that job schedule. I wish I had found this website sooner, so I wouldn’t have to figure out crontab rules in detail and waste time in trial and error!