Platforms
Cron in Jenkins
Jenkins can trigger jobs with cron-like schedules. Jenkins also adds the H token to spread load across projects.
Build periodically
In a Jenkins job, Build periodically accepts cron-like syntax. The H token helps Jenkins choose a stable hashed value.
H/15 * * * * # every 15 minutes, distributed by Jenkins
H 9 * * 1-5 # once around 9 AM on weekdaysBest practices
- Prefer H over hard-coded minute values for many jobs.
- Avoid starting every job at minute 0.
- Document timezone assumptions for controllers and agents.
Common mistakes
- Scheduling many Jenkins jobs at the exact same minute.
- Assuming H means random every run; it is stable hashing.
- Ignoring controller timezone.
FAQ
What does H mean in Jenkins cron?
H is a hash token Jenkins uses to distribute job start times in a stable way.
Can CronTools validate Jenkins H syntax?
CronTools currently validates Linux 5-field cron, so Jenkins H syntax is documentation-only for now.