DocsICP FilingConsole
官方文档
首页

Create CronJobs for scheduled tasks

更新时间：
复制 MD 格式
产品详情
我的收藏

CronJob is a workload that does not manage Pods directly; it creates independent Job instances on a schedule and tracks their status. Use it for periodic tasks such as backups, report generation, or emails. This topic shows how to create a CronJob in the console or with kubectl.

Create a CronJob with the ACK console or kubectl.

Important

The sample images are public. Your cluster needs Internet access to pull them:

  • [Enable Internet access for an existing cluster](https://www.alibabacloud.com/help/en/document_detail/178480.html) (recommended): Create a public NAT gateway for the Virtual Private Cloud (VPC) hosting the cluster to enable Internet access for all resources.

  • [Assign static public IPs to nodes](https://www.alibabacloud.com/help/en/document_detail/2858287.html): Nodes with public IPs can pull public images, but every node running the workload needs a public IP.

Prerequisites

Create a CronJob with the console

  1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

  2. On the Clusters page, click your cluster name. In the left-side pane, choose Workloads > CronJobs.

  3. On the CronJobs page, click Create from Image.

  4. On the Basic Information page, configure basic settings and click Next to go to the Container page.

  5. In the General section, set Image Name to registry.cn-hangzhou.aliyuncs.com/acs-sample/nginx:latest. In the Lifecycle section, configure the Start parameter. Click Next to go to the Advanced page.

    • Command: /bin/sh

    • Parameter: ["-c", "echo 'starting...'; COUNTER=0; while [ $COUNTER -lt 5 ]; do sleep 2; COUNTER=$((COUNTER+1)); echo $COUNTER; done; echo 'finished'; exit 0"]

    Important

    The cluster needs Internet access to pull registry.cn-hangzhou.aliyuncs.com/acs-sample/nginx:latest. If you selected Configure SNAT for VPC during cluster creation, it is already enabled. Otherwise, enable Internet access for the cluster.

    image.png

  6. On the Advanced page, configure scheduling and job settings. For this example, set the schedule to every 2 minutes and keep other options at defaults. Click Create.

    CronJob settings

    Parameter Description
    Schedule Frequency. Choose a preset (hourly, daily, weekly, monthly) or enter a custom cron expression (minute hour day-of-month month day-of-week). See Cron expression syntax.
    Concurrency policy Behavior when a new Job is due while the previous one still runs. Forbid: skip the new Job (for sequential or dependent jobs). Allow: run both concurrently (for independent jobs). Replace: terminate the running Job and start a new one (when only the latest result matters).

    Job history

    Parameter Description
    Successful Jobs History Limit Number of recent successful Jobs to retain. Older ones are deleted.
    Failed Jobs History Limit Number of recent failed Jobs to retain.

    Job settings

    Parameter Kubernetes field Description Default
    Completions jobTemplate.spec.completions Number of Pods that must complete for the Job to succeed. —
    Parallelism jobTemplate.spec.parallelism Maximum number of Pods running concurrently. —
    Timeout jobTemplate.spec.activeDeadlineSeconds Maximum runtime for a Job. The Job stops when this limit is reached, regardless of completion status. 600 seconds
    BackoffLimit jobTemplate.spec.backoffLimit Maximum retries across all Pods before the Job is marked as failed. 6
    Restart jobTemplate.spec.template.spec.restartPolicy Pod restart behavior on failure. Never: restart the container in place without creating a new Pod (restarts don't count toward backoffLimit). On Failure: create a new Pod to replace the failed one. —

    Labels, annotations

    Parameter Description
    Pod Labels Labels added to each Pod. ACK adds app: <application-name> by default. Used to match Pods to workloads and services.
    Pod Annotations Annotations added to each Pod. Some ACK features require specific annotations.

    image.png

  7. Once created, Jobs appear at 2-minute intervals.

    image.png

Create a CronJob with kubectl

Important

Connect to the cluster via kubectl before proceeding.

  1. Save the following YAML as cronjob.yaml. jobTemplate.spec has the same structure as a standalone Job spec.

    apiVersion: batch/v1
kind: CronJob
metadata:
  name: example-cronjob
  labels:
    app: cronjob
spec:
  schedule: "*/2 * * * *"           # Run every 2 minutes
  concurrencyPolicy: Forbid          # Skip new Job if previous one is still running
  successfulJobsHistoryLimit: 3      # Keep the 3 most recent successful Jobs
  failedJobsHistoryLimit: 2          # Keep the 2 most recent failed Jobs
  jobTemplate:
    spec:
      completions: 1                 # Job succeeds after 1 Pod completes
      parallelism: 1                 # Run one Pod at a time
      template:
        spec:
          containers:
          - name: counter
            image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
            command:
            - /bin/sh
            - -c
            - |
              echo "starting...";
              COUNTER=0;
              while [ $COUNTER -lt 5 ]; do
                sleep 2;
                COUNTER=$((COUNTER+1));
                echo "${COUNTER}";
              done;
              echo "finished";
              exit 0
          restartPolicy: Never       # Do not restart the Pod on failure

  2. Apply the manifest:

    kubectl apply -f cronjob.yaml

    Expected output:

    cronjob.batch/example-cronjob created

Verify the CronJob

Confirm the CronJob runs on schedule.

  1. Check the CronJob status:

    kubectl get cronjob example-cronjob

    Expected output:

    NAME               SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
example-cronjob   */2 * * * *   False     0        <none>          15s

    SUSPEND is False, meaning the CronJob is active and triggers on schedule.

  2. After about 10 minutes, list the Jobs created by the CronJob:

    kubectl get job

    Expected output:

    NAME                       STATUS     COMPLETIONS   DURATION   AGE
example-cronjob-2901**22   Complete   1/1           31s        5m13s
example-cronjob-2901**23   Complete   1/1           31s        3m13s
example-cronjob-2901**24   Complete   1/1           26s        73s

    Jobs appear at 2-minute intervals and show Complete status when finished.

  3. Check a Job Pod's logs:

    # List Pods for the most recent Job
kubectl get pods --selector=job-name=<job-name>

# View logs
kubectl logs <pod-name>

    Replace <job-name> with a Job name from the output above (e.g., example-cronjob-2901**24). Successful output ends with finished.

Cron expression syntax

A cron expression consists of five space-separated fields:

# .---------------- minute (0–59)
# |  .------------- hour (0–23)
# |  |  .---------- day of month (1–31)
# |  |  |  .------- month (1–12)
# |  |  |  |  .---- day of week (0–6, Sunday to Saturday)
# |  |  |  |  |
  *  *  *  *  *

Common shorthand entries:

Entry Description Equivalent
@hourly Run once an hour at the start of the hour 0 * * * *
@daily (or @midnight) Run once a day at midnight 0 0 * * *
@weekly Run once a week at midnight on Sunday 0 0 * * 0
@monthly Run once a month at midnight on the first day 0 0 1 * *
@yearly (or @annually) Run once a year at midnight on January 1 0 0 1 1 *

Build and validate cron expressions with crontab.guru.

Next steps

Previous：Create a JobNext：Manage pods