Distribute the load evenly using "H * * * *, not" 5 * * * *

Question

When setting up how Jenkins Shool pulls changes from subversion I tried to check the SCM poll and set the schedule to 5 * * * * , I get the following warning

Distribute the load evenly using "H * * * *, not" 5 * * * *

I'm not sure what H means in this context and why I should use this.

Answer 1

H means hash

In order to periodically carry out the planned tasks in order to ensure an even load on the system, the X symbol (for “hash”) should be used wherever possible. For example, using 0 0 * * * for a dozen daily missions will result in a big splash at midnight. On the contrary, the use of HH * * * will still be performed each work once a day, but not all at the same time, more efficient use of limited resources.

Answer 2

Click on the question mark next to your schedule specification. It says:

In order to periodically carry out the planned tasks in order to ensure an even load on the system, the X symbol (for “hash”) should be used wherever possible. For example, using 0 0 * * * for a dozen daily missions will result in a big splash at midnight. On the contrary, the use of HH * * * will still be performed each work once a day, but not all at the same time, more efficient use of limited resources.

Answer 3

Also in the documentation it is worth noting that:

The character H can be used with a range. For example, HH (0-7) * * * means some time from 12:00 (midnight) to 7:59. You can also use step intervals with H, with or without ranges.

The symbol H can be considered as a random value in the range, but in fact it is a hash of the job name, not a random function, so the value remains stable for any given project.