Running Jenkins periodically

NOTE: This feature is primarily for using Jenkins as a cron replacement, and it is not ideal for continuously building software projects. […] the point of continuous integration is to start a build as soon as a change is made, to provide a quick feedback to the change.¹

In Jenkins go to:
Configure -> Build triggers -> Build periodically -> Schedule

Let’s say you want to run it:
– at 3 a.m.,
– from Monday to Friday,
– each day of the month,
– any month of the year,

then it would be best if you had the following syntax:

Crone syntax
0 3 * * 1-5

where:
– 0 means minutes
– 3 – is 3 a.m.
– * means days of months
– * means all months in the year
– 1-5 means from Monday to Friday

NOTE: Better syntax you can use (you will get the following warning):
Spread load evenly by using ‘H 3 * * 1-5’ rather than ‘0 3 * * 1-5’

Jenkins syntax (recommended)
H 3 * * 1-5

So, why H 3 * * 1-5?

• Load Distribution: Jenkins uses H to spread out jobs across a time window, reducing the chance of system overload at exact times.
• Consistency: H ensures that even though the minute is random, it is consistent across builds for a given job.

By using H 3 * * 1-5, Jenkins will run the job at a random minute within the 3rd hour (between 3:00 and 3:59 AM), Monday to Friday, but it won’t trigger multiple jobs at exactly 3:00 AM.

Let’s see what the documentation says about running it periodically:
This field follows the syntax of cron (with minor differences). Specifically, each line consists of 5 fields separated by TAB or whitespace:

MINUTE HOUR DOM MONTH DOW

MINUTE	Minutes within the hour (0–59)
HOUR	The hour of the day (0–23)
DOM	The day of the month (1–31)
MONTH	The month (1–12)
DOW	The day of the week (0–7) where 0 and 7 are Sunday.

To specify multiple values for one field, the following operators are available. In the order of precedence,
A,B,...,Z enumerates multiple values
* specifies all valid values
M-N specifies a range of vaues
M-N/X or */X steps by intervals of X through the specified range or whole valid rang

1. Jenkins – Help for feature: Build Periodically ↩︎