Help Center/ Cloud Container Engine/ Kubernetes Basics/ Pod Orchestration and Scheduling/ Jobs and CronJobs
Updated on 2025-07-29 GMT+08:00
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Jobs and CronJobs

Overview of Jobs and CronJobs

Jobs and CronJobs are Kubernetes resources designed to manage short-lived, one-off tasks that run to completion.

  • A job is a resource object used to control batch tasks. Jobs start and terminate at specific times, unlike long-running services such as Deployments and StatefulSets, which run continuously unless terminated. Pods managed by a job are automatically removed after successfully completing their tasks, based on the specified settings.
  • A CronJob runs a job periodically on a specified schedule. A CronJob object is similar to a line in a crontab file in Linux.

The run-to-completion feature of workloads makes them particularly suitable for one-off tasks, such as continuous integration (CI) pipelines.

Creating a Job

The following example demonstrates a job that calculates π to the 2000th digit and prints the result. The job is configured to run a total of 50 pods, with up to 5 pods running concurrently. If a pod fails, it can be retried up to 5 times. 
apiVersion: batch/v1
kind: Job
metadata:
  name: pi-with-timeout
spec:
  completions: 50            # The total number of pods that must complete successfully for the job to be considered complete
  parallelism: 5             # The number of pods that can run concurrently. The default value is 1.
  backoffLimit: 5            # The maximum number of retries for a pod if it fails
  activeDeadlineSeconds: 100  # The number of seconds after which the job and all its pods will be terminated
  template:                  # Define the pods for the job.
    spec: 
      containers:
      - name: pi
        image: perl
        command:
        - perl
        - "-Mbignum=bpi"
        - "-wle"
        - print bpi(2000)
      restartPolicy: Never

Based on the completions and Parallelism settings, jobs can be classified into several types.

Table 1 Job types

Job Type

Description

Example

One-off job

The job runs a single pod to completion.

Database migration

Non-parallel job with a fixed completion count

The job runs one pod until the specified completion count is reached.

Processing a queue of tasks

Parallel job with a fixed completion count

The job runs multiple pods in parallel until the specified completion count is reached.

Processing a task queue concurrently

Parallel job

The job runs one or more pods in parallel until one pod completes successfully.

Processing a task queue concurrently

Creating a CronJob

A CronJob is a scheduled job. A CronJob runs a job periodically on a specified schedule, and the job creates pods.

apiVersion: batch/v1
kind: CronJob
metadata:
  name: cronjob-example
spec:
  schedule: "0,15,30,45 * * * *"           # Schedule for the CronJob
  jobTemplate:                             # Define the job.
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
          - name: pi
            image: perl
            command:
            - perl
            - "-Mbignum=bpi"
            - "-wle"
            - print bpi(2000)

The format of the CronJob is as follows:

  • Minute
  • Hour
  • Day of month
  • Month
  • Day of week

Take 0,15,30,45 * * * * as an example. In this example, commas separate the minutes (0, 15, 30, 45). The first asterisk (*) indicates any hour, the second asterisk indicates any day, the third asterisk indicates any month, and the fourth asterisk indicates any day of the week.

If you want to run the job every 30 minutes on the first day of each month, set this parameter to 0,30 * 1 * *. If you want to run the job at 03:00 a.m. every Sunday, set this parameter to 0 3 * * 0.