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 will we learn?¶

• What CronJobs are and how they work in Kubernetes
• How to create, monitor, and manage CronJobs
• How to view Job and Pod outputs from scheduled tasks

Prerequisites¶

• A running Kubernetes cluster (kubectl cluster-info should work)
• kubectl configured against the cluster

Introduction¶

• 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!

Cleanup¶

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?