🚀 How to Create a Kubernetes CronJob (Step-by-Step Guide)

In real-world DevOps environments, teams often need to run tasks on a fixed schedule—such as backups, cleanup jobs, reports, or monitoring scripts.
In Kubernetes, this requirement is fulfilled using CronJobs.

In this blog, we will create a Kubernetes CronJob with a dummy command as part of the Nautilus DevOps team setup.

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🛠 Prerequisites

Before starting, make sure:

• You have access to a Kubernetes cluster

• kubectl is configured correctly

• You are logged into the jump_host
  (In KodeKloud labs, this is already configured)

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📋 Task Requirements

We need to create a CronJob with the following specifications:

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🧠 What is a CronJob in Kubernetes?

A CronJob runs jobs on a time-based schedule, similar to Linux cron.

Examples:

• Every 5 minutes

• Every day at midnight

• Every Sunday

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🧾 Step 1: Create the CronJob YAML File

Create a file named xfusion-cronjob.yaml:

vi xfusion-cronjob.yaml

Paste the following content:

apiVersion: batch/v1
kind: CronJob
metadata:
  name: xfusion
spec:
  schedule: "*/6 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
          - name: cron-xfusion
            image: nginx:latest
            command:
            - /bin/sh
            - -c
            - echo Welcome to xfusioncorp!

💡 Explanation:

• schedule: Runs every 6 minutes

• command: Executes a dummy echo command

• restartPolicy: OnFailure: Pod restarts only if the job fails

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🚀 Step 2: Apply the CronJob

Run the following command:

kubectl apply -f xfusion-cronjob.yaml

Expected output:

cronjob.batch/xfusion created

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🔍 Step 3: Verify the CronJob

Check if the CronJob is created successfully:

kubectl get cronjob xfusion

Sample output:

NAME     SCHEDULE        SUSPEND   ACTIVE   LAST SCHEDULE   AGE
xfusion  */6 * * * *     False     0        <none>          5s

✅ This confirms that the CronJob is running correctly.

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📊 Step 4: (Optional) Check Jobs & Pods

After some time (6 minutes), Kubernetes will create a Job.

kubectl get jobs
kubectl get pods

To check logs:

kubectl logs <pod-name>

Expected log:

Welcome to xfusioncorp!

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⚠️ Common Mistakes to Avoid

❌ Wrong indentation in YAML
❌ restartPolicy outside template.spec
❌ Incorrect container name
❌ Missing quotes around cron schedule

💡 KodeKloud Tip:
Name, schedule, image, and restartPolicy are strictly validated.

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✅ Final Summary

We successfully:

• Created a Kubernetes CronJob

• Used nginx:latest image

• Scheduled it every 6 minutes

• Executed a dummy command

• Ensured correct restart policy

This setup is commonly used as a base template in production DevOps workflows.

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