Cron Job Every 30 Minutes

Cron expression for every 30 minutes

*/30 * * * *

Every 30 minutes. It runs 48 times a day, 17,520 times a year.

Runs on the hour and the half hour. 0,30 * * * * is the same schedule. To run at quarter past and quarter to instead, use 15,45 * * * *.

Field by field

Examples

crontab

Run crontab -e and add:

*/30 * * * * /usr/local/bin/job.sh >> /var/log/job.log 2>&1

Kubernetes CronJob

apiVersion: batch/v1
kind: CronJob
metadata:
  name: my-job
spec:
  schedule: "*/30 * * * *"
  timeZone: "Etc/UTC"          # Kubernetes 1.27+
  concurrencyPolicy: Forbid    # skip a run if the last one is still going
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: job
              image: ghcr.io/acme/job:1.0
          restartPolicy: OnFailure

GitHub Actions

on:
  schedule:
    - cron: '*/30 * * * *'   # UTC

GitHub evaluates schedules in UTC, and runs can start several minutes late at busy times.

systemd timer

# /etc/systemd/system/job.timer
[Unit]
Description=Run job.service every 30 minutes

[Timer]
OnCalendar=*-*-* *:00,30:00
Persistent=true

[Install]
WantedBy=timers.target

Enable it with systemctl enable --now job.timer, and check the next runs with systemd-analyze calendar "*-*-* *:00,30:00". Persistent=true runs a missed job after downtime, which cron can’t do.

AWS EventBridge

cron(0,30 * * * ? *)

EventBridge cron has six fields (the last is the year), uses ? in either the day-of-month or the day-of-week field, and numbers weekdays from 1 (Sunday) to 7. Rules run in UTC; EventBridge Scheduler also accepts a time zone.

Similar schedules: every few minutes

• Every minute: * * * * *
• Every 30 seconds: * * * * *
• Every 2 minutes: */2 * * * *
• Every 3 minutes: */3 * * * *
• Every 5 minutes: */5 * * * *
• Every 10 minutes: */10 * * * *
• Every 15 minutes: */15 * * * *
• Every 20 minutes: */20 * * * *
• Every 45 minutes: */45 * * * *
• Every 5 minutes during business hours: */5 9-17 * * 1-5

Have a different schedule? Paste any expression into the Cron Expression Generator, or browse all cron examples.

Sources

• POSIX: crontab
• crontab(5) manual page
• Kubernetes docs: CronJob
• GitHub Actions docs: schedule event
• systemd.time(7): calendar events
• AWS docs: EventBridge Scheduler cron expressions

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Frequently asked questions