Kubernetes Job

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External

Internal

Overview

A Kubernetes Job is a workload resource that can be used to start and manage Pods to successful completion.

A Pod is considered completed, and thus its execution counted against the completion counter only if finishes successfully. This counter can be configured with .spec.completions. When the specified number of successful completions is reached, the Job is complete. The Job will attempt to restart failed Pods, which don't count against successful executions. The number of retires until the attempts are dropped can be configured with .spec.backoffLimit. For example, to configure a Job to run a Pod once, and give up immediately if it fails, use:

kind: Job
spec:
  completions: 1
  backoffLimit: 0
  [...]

More details on a Job's life cycle is available in the Job Lifecycle section.

The Pods managed by a Job will carry a job-name label with the name of the job, and also a controller-uid label.

Pods can be executed in parallel. The Parallel Execution section provides more details on that.

If the Job needs to execute on a schedule, a CronJob is a better tool.

Manifest

Job Manifest

Get the Log of a Completed Job

kubectl -n <namespace> logs job/<job-name>
kubectl -n test logs job/test-job

Job Lifecycle

Pod and Container Failures

https://kubernetes.io/docs/concepts/workloads/controllers/job/#handling-pod-and-container-failures

Completion

https://kubernetes.io/docs/concepts/workloads/controllers/job/#completion-mode

Suspending a Job

https://kubernetes.io/docs/concepts/workloads/controllers/job/#suspending-a-job

Termination and Cleanup

https://kubernetes.io/docs/concepts/workloads/controllers/job/#job-termination-and-cleanup

Clean up Finished Jobs Automatically

https://kubernetes.io/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically

Jobs that have finished, either "Complete" or "Failed" can be automatically be deleted by using the TTL mechanism provided by the [TTL Controller ]. Set the .spec.ttlSecondsAfterFinished field in the job manifest. If the field is set to 0, the Job will be eligible to be automatically deleted immediately after it finishes.

apiVersion: batch/v1
kind: Job
spec:
  ttlSecondsAfterFinished: 100
  ...

Parallel Execution

https://kubernetes.io/docs/concepts/workloads/controllers/job/#parallel-jobs

Job Alternatives

https://kubernetes.io/docs/concepts/workloads/controllers/job/#alternatives

Set Annotations or Labels on the Job-generated Pods

The labels and annotations set in the .spec.template.metadata section of the job declaration will be injected into the created pods:

apiVersion: batch/v1
kind: Job
spec:
  template:
    metadata:
      labels:
        color: blue
      annotations:       
        example.com/color: red
    spec:
      [...]