Jenkins cron — last day of the month

In a declarative pipeline, the triggers directive accepts multiple cron lines. Each line is a separate trigger; Jenkins fires whichever matches the current time.

pipeline {
  agent any
  triggers {
    cron('''
      0 0 30 4,6,9,11 *
      0 0 31 1,3,5,7,8,10,12 *
      0 0 28 2 *
    ''')
  }
  stages {
    stage('Month-end') {
      steps {
        // ... your last-day-of-month work
      }
    }
  }
}

The triple-quoted string is parsed line-by-line. The Feb 28 line covers non-leap years; for leap-year-safe handling, add a fourth line for Feb 29 plus a runtime check.

A simpler alternative: schedule daily and use a when block to skip non-last-day builds.

pipeline {
  agent any
  triggers {
    cron('H 0 * * *')   // daily at a stable minute past midnight
  }
  stages {
    stage('Month-end work') {
      when {
        expression {
          // True when tomorrow is the 1st (i.e. today is the last day).
          return sh(returnStdout: true, script: "date -d tomorrow +%d").trim() == "01"
        }
      }
      steps {
        // ... your last-day-of-month work
      }
    }
  }
}

The H 0 * * * cron uses the Jenkins H modifier in the minute field — Jenkins picks a stable minute based on the job name hash so the build fires at, say, 00:17 every day instead of 00:00 sharp.

For a Freestyle job (non-pipeline), enter the multi-cron expression in the “Build periodically” box:

# Run on the last day of every month at midnight
0 0 30 4,6,9,11 *
0 0 31 1,3,5,7,8,10,12 *
0 0 28 2 *

Comments (lines starting with #) are accepted in the trigger field — useful for documenting complex multi-cron setups in place.

• SCM polling — if your job triggers on SCM changes too, the build will fire whenever code is pushed, regardless of date. Use the when block to gate the actual work.
• Build queueing — Jenkins can't run two instances of the same job concurrently by default. If your last-day job runs long, the next month's trigger may queue.
• Timezone — Jenkins cron honours the controller's JVM timezone by default. For UTC, set the JVM property -Dorg.apache.commons.jelly.tags.fmt.timeZone=UTC or use a per-trigger TZ prefix.