Creating a Job

Scenario

Jobs are short-lived and run for a certain time to completion. They can be executed immediately after being deployed. It is completed after it exits normally (exit 0).

A job is a resource object that is used to control batch tasks. It is different from a long-term servo workload (such as Deployment and StatefulSet).

A job is started and terminated at specific times, while a long-term servo workload runs unceasingly unless being terminated. The pods managed by a Job automatically exit after the job is completed based on user configurations. The success flag varies depending on the spec.completions policy.

• One-off jobs: A single pod runs once until successful termination.
• Jobs with a fixed success count: N pods run until successful termination.
• Parallel jobs in a work queue: Jobs are considered completed based on the global success confirmed by the application.

Prerequisites

• A cluster is available. For details about how to create a cluster, see Buying a CCE Autopilot Cluster.
• VPC endpoints for accessing SWR and OBS have been configured. For details, see Configuring VPC Endpoints for Accessing SWR and OBS.
• A Service of the LoadBalancer type has been created if the workload needs to be accessed by external networks.
  

  If a pod has multiple containers, the ports used by the containers cannot conflict with each other. If there is a conflict, the Deployment will fail to be created.

Using the CCE Console

1. Log in to the CCE console.
2. Click the cluster name to go to the cluster console, choose Workloads in the navigation pane on the left, and click the Create Workload in the upper right corner.
3. Set basic information about the workload.
   Basic Info

   • Workload Type: Select Job.
   • Workload Name: Enter a name for the workload. Enter 1 to 63 characters starting with a lowercase letter and ending with a lowercase letter or digit. Only lowercase letters, digits, and hyphens (-) are allowed.
   • Namespace: Select a namespace. The default value is default. You can also click Create Namespace to create one. For details, see Creating a Namespace.
   • Pods: Enter the number of pods of the workload.
   Container Settings

   • Container Information
     A pod can have more than one container. You can click Add Container on the right to configure multiple containers.

     • Basic Info: Configure basic information about each container.

       Parameter	Description
       Container Name	Enter a name for the container.
       Pull Policy	Image update or pull policy. If you select Always, the image is pulled from the image repository each time. If you do not select Always, the existing image of the node is preferentially used. If the image does not exist, the image is pulled from the image repository.
       Image Name	Click Select Image and select the image used by the container. To use a third-party image, see Using Third-Party Images.
       Image Tag	Select the image tag to be deployed.
       CPU Quota	CPU limit, which is the maximum CPU available for the container to prevent excessive resource usage.
       Memory Quota	Memory limit, which is the maximum memory available for the container. When the container's memory usage exceeds the memory limit, the container will be terminated.
       (Optional) Init Container	Whether the container will be used as an init container. An init container does not support health check. An init container is a special container that runs before other app containers in a pod are started. Each pod can contain multiple containers. In addition, a pod can contain one or more init containers. Application containers in a pod are started and run only after the running of all init containers completes. For details, see Init Containers.

     • (Optional) Lifecycle: Configure operations to be performed in a specific phase of the container lifecycle, such as Startup Command, Post-Start, and Pre-Stop. For details, see Configuring the Container Lifecycle.
     • (Optional) Environment Variables: Configure variables for the container running environment using key-value pairs. These variables transfer external information to containers running in pods and can be flexibly modified after application deployment. For details, see Configuring Environment Variables.
     • (Optional) Data Storage: Mount local storage or cloud storage to the container. The application scenarios and the ways for mounting the volumes vary with the storage type. For details, see Storage.
   • Image Access Credential: Select the credential used for accessing the image repository. The default value is default-secret. You can use default-secret to access images in SWR. For details about default-secret, see default-secret.
   (Optional) Advanced Settings

   • Labels and Annotations: Add labels or annotations for pods using key-value pairs. After entering the key and value, click Confirm. For details about how to use and configure labels and annotations, see Configuring Labels and Annotations.

   • Job Settings
     • Parallel Pods: Maximum number of pods that can run in parallel during job execution. The value cannot be greater than the total number of pods in the job.
     • Timeout (s): Once a job reaches this time, the job status becomes failed and all pods in this job will be deleted. If you leave this parameter blank, the job will never time out.
     • Completion Mode
       • Non-indexed: A job is considered complete when all the pods are successfully executed. Each pod completion is homologous to each other.
       • Indexed: Each pod gets an associated completion index from 0 to the number of pods minus 1. The job is considered complete when every pod allocated with an index is successfully executed. For an indexed job, pods are named in the format of $(job-name)-$(index).
     • Suspend Job: By default, a job is executed immediately after being created. The job's execution will be suspended if you enable this option, and resumed after you disable it.

4. Click Create Workload in the lower right corner.

Using kubectl

Node affinity and anti-affinity are not available for CCE Autopilot clusters. When you use kubectl to create a workload, do not configure the affinity field to prevent pod creation failures.

A job has the following configuration parameters:

• .spec.completions: indicates the number of pods that need to run successfully to end a job. The default value is 1.
• .spec.parallelism: indicates the number of pods that run concurrently. The default value is 1.
• .spec.backoffLimit: indicates the maximum number of retries performed if a pod fails. When the limit is reached, the pod will not try again.
• .spec.activeDeadlineSeconds: indicates the running time of pods. Once the time is reached, all pods are terminated. .spec.activeDeadlineSeconds has a higher priority than .spec.backoffLimit. If a job reaches .spec.activeDeadlineSeconds, spec.backoffLimit is ignored.

Based on the .spec.completions and .spec.parallelism settings, jobs are classified into the following types.

The following is an example job, which calculates π till the 2000^th digit and prints the output.

apiVersion: batch/v1
kind: Job
metadata:
  name: myjob
spec:
  completions: 50        # 50 pods need to be run to finish a job. In this example, π is printed for 50 times.
  parallelism: 5        # 5 pods are run in parallel.
  backoffLimit: 5        # The maximum number of retry times is 5.
  template:
    spec:
      containers:
      - name: pi
        image: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never
      imagePullSecrets:
        - name: default-secret

Description

• apiVersion: batch/v1 indicates the version of the current job.
• kind: Job indicates that the current resource is a job.
• restartPolicy: Never indicates the current restart policy. For jobs, this parameter can only be set to Never or OnFailure. For other controllers (for example, Deployments), you can set this parameter to Always.

Run the job.

1. Start the job.

   [root@k8s-master k8s]# kubectl apply -f myjob.yaml
   job.batch/myjob created

2. View the job details.

   kubectl get job

   [root@k8s-master k8s]# kubectl get job
   NAME    COMPLETIONS   DURATION   AGE
   myjob   50/50         23s        3m45s

   If the value of COMPLETIONS is 50/50, the job is successfully executed.

3. Query the pod status.

   kubectl get pod

   [root@k8s-master k8s]# kubectl get pod
   NAME          READY   STATUS      RESTARTS   AGE
   myjob-29qlw   0/1     Completed   0          4m5s
   ...

   If the status is Completed, the job is complete.

4. View the pod logs.

   kubectl logs

   # kubectl logs myjob-29qlw
   3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989380952572010654858632788659361533818279682303019520353018529689957736225994138912497217752834791315155748572424541506959508295331168617278558890750983817546374649393192550604009277016711390098488240128583616035637076601047101819429555961989467678374494482553797747268471040475346462080466842590694912933136770289891521047521620569660240580381501935112533824300355876402474964732639141992726042699227967823547816360093417216412199245863150302861829745557067498385054945885869269956909272107975093029553211653449872027559602364806654991198818347977535663698074265425278625518184175746728909777727938000816470600161452491921732172147723501414419735685481613611573525521334757418494684385233239073941433345477624168625189835694855620992192221842725502542568876717904946016534668049886272327917860857843838279679766814541009538837863609506800642251252051173929848960841284886269456042419652850222106611863067442786220391949450471237137869609563643719172874677646575739624138908658326459958133904780275901

Related Operations

After a one-off job is created, you can perform operations listed in Table 2.