Connect to existing pod execute script disconnect - Kubernetes cron job

0 votes

I'm trying to

  1. Connect to an existing Pod
  2. Execute a script
  3. Disconnect

But i cannot find a way to do the same

How do i approach?

Sep 17, 2018 in Kubernetes by Hannah
• 18,540 points
4,778 views

1 answer to this question.

0 votes

As far as i know there's no way to do this.

Instead, a Job can to bring up an instance of your application specifically for running the Job and then take it down once the Job is complete. To do this you can use the same Image for the Job as for your Deployment but use a different "Entrypoint" by setting command:.

If they job needs access to data created by your application then that data will need to be persisted outside the application/Pod, you could so this a few ways but the obvious ways would be a database or a persistent volume. For example useing a database would look something like this:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: APP
spec:
  template:
    metadata:
      labels:
        name: THIS
        app: THAT
    spec:
      containers:
        - image: APP:IMAGE
          name: APP
          command:
          - app-start
          env:
            - name: DB_HOST
              value: "127.0.0.1"
            - name: DB_DATABASE
              value: "app_db"

And a job that connects to the same database, but with a different "Entrypoint" :

apiVersion: batch/v1
kind: Job
metadata:
  name: APP-JOB
spec:
  template:
    metadata:
      name: APP-JOB
      labels:
        app: THAT
    spec:
      containers:
      - image: APP:IMAGE
        name: APP-JOB
        command:
        - app-job
        env:
          - name: DB_HOST
            value: "127.0.0.1"
          - name: DB_DATABASE
            value: "app_db"

Or the persistent volume approach would look something like this:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: APP
spec:
  template:
    metadata:
      labels:
        name: THIS
        app: THAT
    spec:
      containers:
        - image: APP:IMAGE
          name: APP
          command:
          - app-start
          volumeMounts:
          - mountPath: "/var/www/html"
            name: APP-VOLUME
      volumes:
        - name:  APP-VOLUME
          persistentVolumeClaim:
            claimName: APP-CLAIM

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: APP-VOLUME
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  nfs:
    path: /app

---

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: APP-CLAIM
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi
  selector:
    matchLabels:
      service: app

With a job like this, attaching to the same volume:

apiVersion: batch/v1
kind: Job
metadata:
  name: APP-JOB
spec:
  template:
    metadata:
      name: APP-JOB
      labels:
        app: THAT
    spec:
      containers:
      - image: APP:IMAGE
        name: APP-JOB
        command:
        - app-job
        volumeMounts:
        - mountPath: "/var/www/html"
          name: APP-VOLUME
    volumes:
      - name:  APP-VOLUME
        persistentVolumeClaim:
          claimName: APP-CLAIM
answered Sep 17, 2018 by Kalgi
• 52,360 points

Related Questions In Kubernetes

0 votes
1 answer

Kubernetes cron job call curl in loop

It's a small silly mistake: dollar sign $ should be ...READ MORE

answered Sep 17, 2018 in Kubernetes by Kalgi
• 52,360 points
8,946 views
0 votes
1 answer

Why do jobs have to be idempotent - kubernetes cron jobs

To understand why this happens lets for ...READ MORE

answered Sep 17, 2018 in Kubernetes by Kalgi
• 52,360 points
2,639 views
0 votes
1 answer

How to fail a (cron) job after a certain number of retries?

You're trying to set 3 asbackoffLimit of your Job. ...READ MORE

answered Sep 17, 2018 in Kubernetes by Kalgi
• 52,360 points
3,077 views
0 votes
3 answers

Change the schedule of Kubernetes cron job

kubectl patch <backup-cronjob> -p '{"spec":{"schedule": "0 0 ...READ MORE

answered Jun 21, 2019 in Kubernetes by sudhams reddy duba
7,176 views
+1 vote
1 answer
0 votes
3 answers

Error while joining cluster with node

Hi Kalgi after following above steps it ...READ MORE

answered Jan 17, 2019 in Others by anonymous
15,335 views
+4 votes
1 answer

Installing Web UI (Dashboard):kubernetes-dashboard on main Ubuntu 16.04.6 LTS (Xenial Xerus) server

Follow these steps: $ kubeadm reset $ kubeadm init ...READ MORE

answered Apr 12, 2019 in Kubernetes by Kalgi
• 52,360 points

reshown Apr 12, 2019 by Kalgi 6,948 views
+1 vote
4 answers

Execute shell script file using kubernetes as a cron job

use /bin/sh instead of /bin/bash This solved it ...READ MORE

answered May 7, 2019 in Kubernetes by Sid
17,645 views
0 votes
1 answer

Not able to access kubernetes api from a pod in azure

Follow these steps Add --bind-address=0.0.0.0 option to the line https://github.com/kubernetes/kubernetes/blob/v1.2.0/docs/getting-started-guides/coreos/azure/cloud_config_templates/kubernetes-cluster-main-nodes-template.yml#L218  Created ...READ MORE

answered Aug 30, 2018 in Kubernetes by Kalgi
• 52,360 points
988 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP