kubernetes cronjob executed many times

Question

this is my kubernetes CronJob definition:

apiVersion: batch/v1
kind: CronJob
metadata:
  name: job-monitor
  namespace: cronjobs
  labels:
    app: job-monitor
spec:
  schedule: "15 */6 * * *"
  successfulJobsHistoryLimit: 3
  failedJobsHistoryLimit: 3
  concurrencyPolicy: Replace
  jobTemplate:
    spec:
      template:
        spec:
          nodeSelector:
            agentpool: streaming
          restartPolicy: OnFailure
          containers:
            - name: job-monitor
              image: imageRepository:latest
              securityContext:
                capabilities:
                  add:
                    - NET_ADMIN
              resources:
                requests:
                  cpu: "2000m"
                  memory: "4000Mi"
                limits:
                  cpu: "3000m"
                  memory: "6000Mi"

It gets executed @minute 15 but it get executed more than once so every minute. One day I saw the alert comming every minute @2:15, 2:16, 2:16, 2:18, 2:20 The other day @2:15, 2:16, 2:17, 2:18, 2:21.

Why?

Answer 1

As I checked the above comments and Answer:

You want to run the Job every 6 hours starting at minute 15 of the hour during Mon-Sun. So per day it runs 4 times.

If it starts from 0:15 min, 6:15 min, 12:15 min, 18:15 min again it repeats the same for the next day..

Syntax is:

15 */6 * * 1-7

Output :

I have tried the above cron job syntax and it's working fine.

If you find any errors let me know .

Answer 2

The first item in a cron schedule is the minute. The first * in your cron schedule * 7,19 * * * matches every minute between 7:00 and 7:59 (and also every minute between 19:00 and 19:59). In theory, your cron job should not run twice, but 120 times per day using this schedule. To execute your cron job at exactly 7:00 and 19:00, use 0 7,19 * * * as schedule.

For reference, the Kubernetes documentation on CronJob resources contains more information on the cron schedule format and itself links to the BSD cron documentation .

And also refer to these documents for more information for cron jobs execution .