Jenkins Cron Syntax
Jenkins uses a 5-field cron for build triggers with one extra symbol: H (hash). H picks a stable pseudo-random value in the field's range so builds are spread out instead of all firing at :00. Use H/15 to run roughly every 15 minutes.
The trigger
In a job's Build Triggers → Build periodically (or triggers { cron('...') } in a Jenkinsfile):
H/15 * * * * runs about every 15 minutes, but Jenkins offsets the start minute per job so all jobs don't hammer the controller at once.
What H does
H is a hash of the job name, giving a fixed but spread-out value. H H(0-7) * * * runs once a day at a stable random minute between midnight and 7:59 AM. Prefer H over fixed minutes for load spreading.
Fields
MINUTE HOUR DOM MONTH DOW — same order as Unix cron. Day-of-week is 0–7 (0 and 7 are Sunday). Aliases like @daily and @midnight also work.
Common examples
H 2 * * * once a day around 2 AM; H/30 9-17 * * 1-5 every ~30 min during business hours on weekdays; H H 1 * * once on the 1st of each month.
FAQ
What does H mean in Jenkins cron?
H (hash) picks a stable value based on the job name so builds spread out across the field's range instead of all firing at the same minute. H/15 means roughly every 15 minutes, offset per job.
Is Jenkins cron the same as Unix cron?
Same 5 fields and order, but Jenkins adds the H symbol and aliases like @daily. Standard expressions like 0 2 * * * still work.
How do I run a Jenkins job every weekday at business hours?
H/30 9-17 * * 1-5 runs about every 30 minutes from 9 AM to 5 PM, Monday to Friday, spread out via H.