CronJobs¶

• In this lab, we will learn how to create and manage CronJobs in Kubernetes.
• A CronJob creates Jobs on a time-based schedule. It is useful for running periodic and recurring tasks, such as backups or report generation.

What is a CronJob?¶

• A CronJob in Kubernetes runs Jobs on a time-based schedule, similar to Linux cron.
• Useful for periodic tasks like backups, reports, or cleanup.

Step - 01: Create a CronJob YAML¶

• Create a file named hello-cronjob.yaml with the following content:

apiVersion: batch/v1
kind: CronJob
metadata:
    name: hello
    namespace: default
spec:
    schedule: "*/1 * * * *" # Every 1 minute
    jobTemplate:
        spec:
            template:
                spec:
                    containers:
                    - name: hello
                        image: busybox
                        args:
                        - /bin/sh
                        - -c
                        - date; echo Hello from the Kubernetes CronJob!
                    restartPolicy: OnFailure

Step - 02: Apply the CronJob¶

kubectl apply -f hello-cronjob.yaml

Step - 03: Verify CronJob Creation¶

kubectl get cronjob hello

Step - 04: Check CronJob and Jobs¶

• List CronJobs:

kubectl get cronjobs

• List Jobs created by the CronJob:

kubectl get jobs

• List Pods created by Jobs:

kubectl get pods

Step - 05: View Job Output¶

• Get the name of a pod created by the CronJob, then view its logs:

kubectl logs <pod-name>

Example output:

Mon Nov 10 12:00:00 UTC 2025
Hello from the Kubernetes CronJob!

Step - 06: Clean Up¶

• Delete the CronJob and its Jobs:

kubectl delete cronjob hello
kubectl delete jobs --all

Questions:¶

• What happens if the job takes longer than the schedule interval?
• How would you change the schedule to run every 5 minutes?
• How can you limit the number of successful or failed jobs to keep?