<p>I have a Kubernetes Job that has, for instance, parallelism set to 4. When this job is created, I might want to scale this out to, say, 8. But it seems like <code>edit</code>ing the Job and setting parallelism to 8 doesn't actually create more pods in the Job.</p>
<p>Am I missing something? Or is there no way to scale out a Job?</p>

<p>So as per <a href="https://cloud.google.com/kubernetes-engine/docs/how-to/jobs" rel="noreferrer">job documentation</a> you can still scale a Job running the following command:</p>

<pre><code>kubectl scale job my-job --replicas=[VALUE]
</code></pre>

<p>Simple test shows that this option works right now as expected, but will be really deprecated in a future</p>

<blockquote>
  <p>kubectl scale job is DEPRECATED and will be removed in a future
  version.</p>
  
  <p>The ability to use kubectl scale jobs is deprecated. All other scale
  operations remain in place, but the ability to scale jobs will be
  removed in a future release.</p>
</blockquote>

<p>The reason is: <a href="https://github.com/kubernetes/kubernetes/pull/60139" rel="noreferrer">Deprecate kubectl scale job</a></p>

<p>Use below Job yaml as an example to create job:</p>

<pre><code>apiVersion: batch/v1
kind: Job
metadata:
  name: test-job
spec:
  template:
    spec:
      containers:
      - name: pi
        image: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2010)"]
      restartPolicy: Never
  completions: 1000
  parallelism: 5
</code></pre>

<p>Now lets test behavior:</p>

<pre><code>kubectl describe jobs.batch test-job 
Parallelism:    5
Completions:    1000
Start Time:     Fri, 17 May 2019 16:58:36 +0200
Pods Statuses:  5 Running / 21 Succeeded / 0 Failed


kubectl get pods | grep test-job | grep Running
test-job-98mlv           1/1     Running     0          13s
test-job-fs2hb           1/1     Running     0          8s
test-job-l8n6v           1/1     Running     0          16s
test-job-lbh46           1/1     Running     0          13s
test-job-m8btl           1/1     Running     0          2s
</code></pre>

<p>Changing  parallelism with <code>kubectl scale</code>:</p>

<pre><code>kubectl scale jobs.batch test-job --replicas=10

kubectl describe jobs.batch test-job
Parallelism:    10
Completions:    1000
Start Time:     Fri, 17 May 2019 16:58:36 +0200
Pods Statuses:  10 Running / 87 Succeeded / 0 Fail

kubectl get pods | grep test-job | grep Running
test-job-475zf           1/1     Running     0          10s
test-job-5k45h           1/1     Running     0          14s
test-job-8p99v           1/1     Running     0          22s
test-job-jtssp           1/1     Running     0          4s
test-job-ltx8f           1/1     Running     0          12s
test-job-mwnqb           1/1     Running     0          16s
test-job-n7t8b           1/1     Running     0          20s
test-job-p4bfs           1/1     Running     0          18s
test-job-vj8qw           1/1     Running     0          18s
test-job-wtjdl           1/1     Running     0          10s
</code></pre>

<p>And the last step that i believe will be the most interesting for you - you can always edit your job using <a href="https://kubernetes.io/docs/tasks/run-application/update-api-object-kubectl-patch/" rel="noreferrer">kubectl patch</a> command</p>

<pre><code>kubectl patch job test-job -p '{"spec":{"parallelism":15}}'

kubectl describe jobs.batch test-job
Parallelism:    15
Completions:    1000
Start Time:     Fri, 17 May 2019 16:58:36 +0200
Pods Statuses:  15 Running / 175 Succeeded / 0 Failed

kubectl get pods | grep test-job | grep Running | wc -l
15
</code></pre>
