How to Create Jobs in Kubernetes

Intro

Jobs in Kubernetes allow us to run one offs or recurring tasks using containers in our cluster. Common use cases for this are running one off reports from a database query, running tests during a CI/CD pipeline, or running cron jobs to send emails, cache data, and more. In this article, we will learn how to use Jobs in Kubernetes.

The Quick Answer

If you are here for the quick answer, here it is. Otherwise, continue to Getting Started.

Save the following to a file job.yaml

apiVersion: v1
kind: Job
metadata:
   name: MyCronJob
spec:
   schedule: h/30 * * * * ?
   template:
      metadata
         name: py
      spec:
         containers:
         - name: py
         image: python
         command: ["python",  "index.py"]
restartPolicy: OnFailure

Then use the following command.

kubectl apply -f job.yaml --namespace=my-example-namespace

Getting Setup

We will be working with minikube for most tutorials. This creates a local kubernetes cluster that you can develop on.

• See this page for setup instructions https://minikube.sigs.k8s.io/docs/start/

Feel free to use another kubernetes cluster for these tutorials as well. There will be articles underneath our kubernetes tags on how to run clusters on multiple providers such as AWS, Google Cloud, and Azure.

Once you have minikube installed, start the cluster using the following command.

minikube start

Creating a Job

To create a job, we will first need a yaml file to store our job information. Create a new file

touch job.yaml

Now, let's add the first two lines

apiVersion: v1
kind: Job

This states that we will use the apiVersion of version 1 and the kind of resource will be a job.

Next, let's add some metadata. This tell kubernetes to name our job and store it in a namespace. This helps for searching and managing our resources.

metadata:
  name: my-job
  namespace: my-example-namespace

Now we defined the spec for our job. There are two main fields, schedule, which represents the cron to run this if we are doing a cron job, and template which represents a pod spec.

spec:
   schedule: h/30 * * * * ?
   template:
      metadata
         name: py
      spec:
         containers:
         - name: py
         image: python
         command: ["python",  "index.py"]
restartPolicy: OnFailure

Notice that we have one container, but we could add more. Now, our file should look like the following.

apiVersion: v1
kind: Job
metadata:
   name: MyCronJob
spec:
   schedule: h/30 * * * * ?
   template:
      metadata
         name: py
      spec:
         containers:
         - name: py
         image: python
         command: ["python",  "index.py"]
restartPolicy: OnFailure

Now, to deploy this job, we can use the following command, assuming your terminal is in the same directory as the file.

kubectl apply -f job.yaml --namespace= my-example-namespace

You can view your job information using the following

kubectl get job my-job --namespace=my-example-namespace