31

It is how to run simple batch in kubernetes yaml (helloworld.yaml):

...
image: "ubuntu:14.04"
command: ["/bin/echo", "hello", "world"]
...

In Kubernetes i can deploy that like this:

$ kubectl create -f helloworld.yaml

Suppose i have a batch script like this (script.sh):

#!/bin/bash
echo "Please wait....";
sleep 5

Is there way to include the script.sh into kubectl create -f so it can run the script. Suppose now helloworld.yaml edited like this:

...
image: "ubuntu:14.04"
command: ["/bin/bash", "./script.sh"]
...
smftr
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2 Answers2

44

I'm using this approach in OpenShift, so it should be applicable in Kubernetes as well.

Try to put your script into a configmap key/value, mount this configmap as a volume and run the script from the volume.

apiVersion: batch/v1
kind: Job
metadata:
  name: hello-world-job
spec:
  parallelism: 1    
  completions: 1    
  template:         
    metadata:
      name: hello-world-job
    spec:
      volumes:
      - name: hello-world-scripts-volume
        configMap:
          name: hello-world-scripts
      containers:
      - name: hello-world-job
        image: alpine
        volumeMounts:
          - mountPath: /hello-world-scripts
            name: hello-world-scripts-volume
        env:
          - name: HOME
            value: /tmp
        command:
        - /bin/sh
        - -c
        - |
          echo "scripts in /hello-world-scripts"
          ls -lh /hello-world-scripts
          echo "copy scripts to /tmp"
          cp /hello-world-scripts/*.sh /tmp
          echo "apply 'chmod +x' to /tmp/*.sh"
          chmod +x /tmp/*.sh
          echo "execute script-one.sh now"
          /tmp/script-one.sh
      restartPolicy: Never
---
apiVersion: v1
items:
- apiVersion: v1
  data:
    script-one.sh: |
      echo "script-one.sh"
      date
      sleep 1
      echo "run /tmp/script-2.sh now"
      /tmp/script-2.sh
    script-2.sh: |
      echo "script-2.sh"
      sleep 1
      date
  kind: ConfigMap
  metadata:
    creationTimestamp: null
    name:  hello-world-scripts
kind: List
metadata: {}
Aldjinn
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    I just want to stress the importance of `restartPolicy: Never`, because otherwise you might get `CrashLoopBackOff`s. [See here](https://stackoverflow.com/a/50794554/308451). – JBSnorro Mar 19 '20 at 15:48
  • Hey @JBSnorro thanks for the comment. My doubt is what happens if we set the `restartPolicy: Never` and our script fails due to some error? – aru_sha4 Feb 01 '21 at 12:07
  • can we bash over shell in pod – prince yadav Sep 15 '21 at 05:43
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    Is there a need to use the list object? I was able to use multiple scripts and execute them as specified in the answer using a deployment without using list. But i am not able to figure out why list was used in the answer. Can anyone help please – Shaiju Janardhanan Sep 27 '21 at 09:46
  • Why do we get the `CrashLoopBackOff` if we do not define the `restartPolicy`? – User12547645 Oct 20 '21 at 14:35
14

As explained here, you could use the defaultMode: 0777 property as well, an example:

apiVersion: v1
kind: ConfigMap
metadata:
  name: test-script
data:
  test.sh: |
    echo "test1"
    ls
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: test
spec:
  selector:
    matchLabels:
      app: test
  template:
    metadata:
      labels:
        app: test
    spec:
      volumes:
      - name: test-script
        configMap:
          name: test-script
          defaultMode: 0777
      containers:
      - command:
        - sleep
        - infinity
        image: ubuntu
        name: locust
        volumeMounts:
          - mountPath: /test-script
            name: test-script

You can enter into the container shell and execute the script /test-script/test.sh

ruloweb
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