Kubernetes - Parallelism in Jobs

If the job does not have any dependency between them, we can have the job run in parallel. Lets create a job that lets the pods run in parallel,

[root@manja17-I13330 kubenetes-config]# cat basic-parallelism-job.yml

apiVersion: batch/v1

kind: Job

metadata:

  name: testing-service

spec:

  parallelism: 3

  template:

    metadata:

      labels:

        name: testing-service

    spec:

      containers:

      - name: counter

        image: centos:7

        command:

          - "bin/bash"

          - "-c"

          - "for i in 9 8 7 6 5 4 3 2 1 ; do echo $i ; done"

      restartPolicy: Never

[root@manja17-I13330 kubenetes-config]# kubectl create -f basic-parallelism-job.yml

job.batch "testing-service" created

[root@manja17-I13330 kubenetes-config]# kubectl get jobs

NAME                DESIRED   SUCCESSFUL   AGE

testing-service   <none>     2                    4s

[root@manja17-I13330 kubenetes-config]# kubectl get pods

NAME                        READY     STATUS      RESTARTS   AGE

testing-service-4jq5r   0/1       Completed    0                7s

testing-service-ltlq4    0/1       Completed    0                7s

testing-service-vjn2w  0/1       Completed    0                7s

Describe the job using,

[root@manja17-I13330 kubenetes-config]# kubectl describe job testing-service

Name:           testing-service

Namespace:      default

Selector:       controller-uid=3eb65bba-8f0d-11e8-a791-020055e1ea1d

Labels:         controller-uid=3eb65bba-8f0d-11e8-a791-020055e1ea1d

                job-name=testing-service

                name=testing-service

Annotations:    <none>

Parallelism:    3

Completions:    <unset>

Start Time:     Tue, 24 Jul 2018 02:46:08 -0400

Pods Statuses:  0 Running / 3 Succeeded / 0 Failed

Pod Template:

  Labels:  controller-uid=3eb65bba-8f0d-11e8-a791-020055e1ea1d

           job-name=testing-service

           name=testing-service

  Containers:

   counter:

    Image:      centos:7

    Port:       <none>

    Host Port:  <none>

    Command:

      bin/bash

      -c

      for i in 9 8 7 6 5 4 3 2 1 ; do echo $i ; done

    Environment:  <none>

    Mounts:       <none>

  Volumes:        <none>

Events:

  Type    Reason            Age   From            Message

  ----    ------            ----  ----            -------

  Normal  SuccessfulCreate  15s   job-controller  Created pod: testing-service-vjn2w

  Normal  SuccessfulCreate  15s   job-controller  Created pod: testing-service-4jq5r

  Normal  SuccessfulCreate  15s   job-controller  Created pod: testing-service-ltlq4