Jobs and CronJobs

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 task (ie, Job) is complete. Deleting a Job will clean up the Pods it created.

CronJobs

One CronJob object is like one line of a crontab (cron table) file. It runs a job periodically on a given schedule, written in Cron format.

All CronJob schedule: times are based on the timezone of the master where the job is initiated.

Resources

OpenShiftKubernetes

Automated Tasks with Cron

References

It computes π to 2000 places and prints it out

apiVersion: batch/v1
kind: Job
metadata:
  name: pi
spec:
  template:
    spec:
      containers:
        - name: pi
          image: perl
          command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never
  backoffLimit: 4

Running in parallel

apiVersion: batch/v1
kind: Job
metadata:
  name: pi
spec:
  parallelism: 2
  completions: 3
  template:
    spec:
      containers:
        - name: pi
          image: perl
          command: ["perl", "-Mbignum=bpi", "-wle", "print bpi(2000)"]
      restartPolicy: Never
  backoffLimit: 4

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: hello
spec:
  schedule: "*/1 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: hello
              image: busybox
              args:
                - /bin/sh
                - -c
                - date; echo Hello from the Kubernetes cluster
          restartPolicy: OnFailure

OpenShiftKubernetes

Gets Jobs

oc get jobs

Gets Job Description

oc describe job pi

Gets Pods from the Job

oc get pods

Deletes Job

oc delete job pi

Gets CronJob

oc get cronjobs

Describes CronJob

oc describe cronjobs pi

Gets Pods from CronJob

oc get pods

Deletes CronJob

oc delete cronjobs pi