K8s tips: Manually launch a Job from CronJob

DevOps
k8s, kubernetes, tips

You just applied your new CronJob to Kubernetes and now would you like to try it?

You need to run your CronJob one time out of schedule?

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apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: my-cj
spec:
  schedule: "0 08 * * SAT"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: my-cj-pod
              image: "my-cj-image:latest"

The first thing that could come to your mind is to temporarily change the schedule to make it run ASAP, but there is a smarter way to create a Job defined in a CronJob.

Solution

Kubectl v1.10.1+ introduced the kubectl create job command with a --from option that actually accepts only a CronJob.

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kubectl -n my-ns create job --from=cronjob/my-cj my-job-name

This command will instantly create a Job named my-job-name from the jobTemplate of the CronJob named my-cj.