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How can I run a cron job every 15 mins on Jenkins?

This is what I've tried :

On Jenkins I have a job set to run every 15 mins using this cron syntax :

14 * * * *

But the job executes every hour instead of 15 mins.

I'm receiving a warning about the format of the cron syntax : 

Spread load evenly by using ‘H * * * *’ rather than ‘14 * * * *’

Could this be the reason why the cron job executes every hour instead of 15 mins ?

blue-sky
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3 Answers3

91

Your syntax is slightly wrong. Say:

*/15 * * * * command
  |
  |--> `*/15` would imply every 15 minutes.

* indicates that the cron expression matches for all values of the field.

/ describes increments of ranges.

devnull
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79

1) Your cron is wrong. If you want to run job every 15 mins on Jenkins use this:

H/15 * * * *

2) Warning from Jenkins Spread load evenly by using ‘...’ rather than ‘...’ came with JENKINS-17311:

To allow periodically scheduled tasks to produce even load on the system, the symbol H (for “hash”) should be used wherever possible. For example, using 0 0 * * * for a dozen daily jobs will cause a large spike at midnight. In contrast, using H H * * * would still execute each job once a day, but not all at the same time, better using limited resources.

Examples:

  • H/15 * * * * - every fifteen minutes (perhaps at :07, :22, :37, :52):
  • H(0-29)/10 * * * * - every ten minutes in the first half of every hour (three times, perhaps at :04, :14, :24)
  • H 9-16/2 * * 1-5 - once every two hours every weekday (perhaps at 10:38 AM, 12:38 PM, 2:38 PM, 4:38 PM)
  • H H 1,15 1-11 * - once a day on the 1st and 15th of every month except December
lu_ko
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    Using "H/15 * * * *" will trigger the following inline error: `Invalid input: "H/15 * * * *": line 1:2: unexpected token: /` – matthieus Jun 27 '14 at 16:13
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    Not sure if the above comment is relevant as the `H` is specific to [jenkins](https://stackoverflow.com/questions/47302607/meaning-of-h-5-in-cron-jenkins) – dannypaz Nov 26 '18 at 22:38
  • I'm getting "unexpected token: /" as well when using forward slash in any cron increment/range specification like the OP needs. I have tried single/double quotes, escaping slash with backslash. What's the solution? – timblaktu Mar 02 '20 at 20:05
  • For those who may wonder: we have more than a dozen jenkins controllers, each with the same job in the same folder. "H * * * *" makes them all run every day at the SAME TIME. – Steven the Easily Amused Jun 05 '22 at 18:24
10

It should be,

*/15 * * * *  your_command_or_whatever
sat
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