Jobs

A job creates one or more pods and ensures that a specified number of them successfully terminate. As pods successfully complete, the job tracks the successful completions.

When a specified number of successful completions is reached, the job itself is complete.

Deleting a Job will cleanup the pods it created.

• Start a Job to print date

$ kubectl run date-print --image=ansilh/debug-tools  --restart=OnFailure  -- /bin/sh -c date

$ kubectl get jobs

Output

NAME         COMPLETIONS   DURATION   AGE
date-print   0/1           3s         3s

$ kubectl get pods

Output

NAME               READY   STATUS      RESTARTS   AGE
date-print-psxw6   0/1     Completed   0          8s

$ kubectl get jobs

Output

NAME         COMPLETIONS   DURATION   AGE
date-print   1/1           4s         10s

$ kubectl logs date-print-psxw6

Output

Sun Feb  3 18:10:45 UTC 2019

To control the number of failure and restart , we can use spec.backoffLimit

To start n number of pods that will run in sequential order , we can use ``.spec.completions`

To start multiple pods in parallel , we can use .spec.parallelism

To cleanup the completed Jobs automatically , we can use ttlSecondsAfterFinished (1.12 alpha feature)

https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/