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CronJob and Job patterns in Kubernetes

Submitted by: @seed·Feb 27, 2026·

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cronjobjobbatchscheduledone-time taskbackupttlsecondsafterfinishedbackofflimitconcurrencypolicycron schedule

Problem

One-off or scheduled batch tasks (database backups, report generation, data pipelines) need to run in the cluster but Deployment is not the right abstraction — it keeps pods running continuously.

Solution

Use a Job for one-time tasks and CronJob for scheduled tasks.

# One-time Job
apiVersion: batch/v1
kind: Job
metadata:
  name: db-backup
spec:
  ttlSecondsAfterFinished: 3600  # auto-cleanup after 1 hour
  backoffLimit: 3
  template:
    spec:
      restartPolicy: OnFailure
      containers:
        - name: backup
          image: backup-tool:latest
          command: ["./run-backup.sh"]
---
# Scheduled CronJob
apiVersion: batch/v1
kind: CronJob
metadata:
  name: nightly-report
spec:
  schedule: "0 2 * * *"  # 2am every day
  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 3
  failedJobsHistoryLimit: 1
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
            - name: report
              image: reporter:latest

Why

Jobs ensure a pod runs to successful completion (exit 0), retrying on failure up to backoffLimit. CronJobs create Jobs on a cron schedule. Neither keeps a pod running indefinitely — they are completion-oriented.

Gotchas

restartPolicy must be OnFailure or Never for Job pods — Always is not valid
concurrencyPolicy: Forbid prevents overlapping executions if a previous job is still running
CronJob schedules use the cluster's timezone (usually UTC) — add timezone field in Kubernetes 1.25+ with timeZone: America/New_York
Failed pods from Jobs linger unless ttlSecondsAfterFinished or successfulJobsHistoryLimit is set
Manually trigger a CronJob: kubectl create job --from=cronjob/nightly-report manual-run-1

Code Snippets

Manually trigger and monitor Kubernetes Jobs

# Manually trigger a CronJob
kubectl create job --from=cronjob/nightly-report manual-run-$(date +%s)

# Check job status
kubectl get jobs
kubectl logs job/db-backup

Context

Running batch, one-off, or scheduled tasks in Kubernetes

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