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Convert Quartz cron to Kubernetes
Quartz expressions look similar to Kubernetes, but the differences matter. Paste yours below; the result is checked against the original run times.
What changes from Quartz to Kubernetes
- Kubernetes has no seconds field, so a schedule that fires on specific seconds cannot be converted exactly. The seconds value is dropped and flagged.
- Quartz numbers weekdays 1-7 starting on Sunday. Kubernetes starts on Sunday = 0, so every weekday number is reduced by one.
- Kubernetes does not use
?, so it is replaced with*. - Kubernetes has no year field. A specific year would be dropped, so the schedule would repeat every year; the converter warns you.
- Quartz requires both day fields to match; Kubernetes fires when either does. Schedules that restrict both are flagged.
- Kubernetes has no
L,Wor#symbols. Schedules like "last day of the month" cannot be converted and are refused rather than silently changed.
Worked examples
| Schedule | Quartz | Kubernetes |
|---|---|---|
| every minute | 0 * * * * ? | * * * * * |
| every 5 minutes | 0 */5 * * * ? | */5 * * * * |
| every 10 minutes | 0 */10 * * * ? | */10 * * * * |
| every 15 minutes | 0 */15 * * * ? | */15 * * * * |
| every 30 minutes | 0 */30 * * * ? | */30 * * * * |
| every hour | 0 0 * * * ? | 0 * * * * |
| every 2 hours | 0 0 */2 * * ? | 0 */2 * * * |
| every 3 hours | 0 0 */3 * * ? | 0 */3 * * * |
Conversions that come with a warning
- every 10 seconds:
0/10 * * * * ?โ* * * * *. Kubernetes CronJob has no seconds field; the seconds value "0/10" was dropped. - every 30 seconds:
0/30 * * * * ?โ* * * * *. Kubernetes CronJob has no seconds field; the seconds value "0/30" was dropped.
What cannot be converted
These common Quartz schedules have no equivalent in Kubernetes. The converter refuses them instead of guessing.
- on the last day of every month:
0 0 0 L * ?. This schedule cannot be expressed in Kubernetes CronJob: "L" is not a valid dom value. - on the first Monday of every month at 9:00 AM:
0 0 9 ? * 2#1. This schedule cannot be expressed in Kubernetes CronJob: "1#1" is not a valid dow value. - on the last Friday of every month at noon:
0 0 12 ? * 6L. This schedule cannot be expressed in Kubernetes CronJob: "5L" is not a valid dow value.
Field layout and time zones
second (0-59), minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), day-of-week (1-7, 1 = Sunday), year (1970-2199, optional).
Quartz uses the JVM default time zone unless you set one: CronScheduleBuilder.cronSchedule(expr).inTimeZone(TimeZone.getTimeZone("UTC")).
minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), day-of-week (0-7, 0 and 7 = Sunday).
Set spec.timeZone (Kubernetes 1.27+) to a name like Asia/Kolkata. Without it the schedule follows the controller's time zone, usually UTC.
Go the other way
Convert Kubernetes to Quartz, or open the Quartz builder or the Kubernetes builder.
Frequently asked questions
How do I convert a Quartz cron expression to Kubernetes?
Paste it into the converter above with Quartz as the source and Kubernetes as the target. For example, 0 * * * * ? becomes * * * * *.
Is every Quartz expression convertible to Kubernetes?
No. Out of 32 common schedules, 3 cannot be expressed in Kubernetes: on the last day of every month; on the first Monday of every month at 9:00 AM; on the last Friday of every month at noon.
Does Kubernetes run in the same time zone as Quartz?
Not necessarily. Conversion changes the syntax, not the time zone. Check where each system evaluates the schedule before you rely on the same clock times.