Jobs & CronJobs

Not all Kubernetes workloads run forever. Sometimes, you just need to run something once—or on a schedule. That’s where Jobs and CronJobs come in.

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Jobs

A Job runs a Pod (or Pods) to completion. Perfect for: - One-time tasks - Batch processing - Migrations or post-deployment hooks

Kubernetes guarantees the Job runs to completion—even if a Pod crashes or a node fails, a new Pod will be scheduled.

Minimal Job Example

kind: Job
spec:
  template:
    spec:
      containers:
        - name: hello
          image: busybox
          command: ["echo", "Hello World"]
      restartPolicy: Never

Tip: The restartPolicy for Jobs must be Never or OnFailure.

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CronJobs

A CronJob runs Jobs on a repeating schedule, just like Linux cron.

Use CronJobs for: - Periodic cleanup tasks - Scheduled reports - Time-based batch jobs

Cron Syntax Example

kind: CronJob
spec:
  schedule: "0 * * * *"  # every hour
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: task
              image: busybox
              args: ["echo", "Hourly job"]
          restartPolicy: OnFailure

CronJobs use the same jobTemplate spec as regular Jobs.

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Cron Syntax Quick Guide

Field	Meaning
Minute	0–59
Hour	0–23
Day of Month	1–31
Month	1–12
Day of Week	0–6 (Sun=0)

Examples: - 0 0 * * * = Every day at midnight - */5 * * * * = Every 5 minutes

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Summary

• Use a Job for tasks that need to run once and finish.
• Use a CronJob to schedule Jobs using cron syntax.
• Both are useful for batch jobs, cleanup scripts, and other non-service workloads.