Running Automated Tasks with a CronJob

    • You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using or you can use one of these Kubernetes playgrounds:

    Cron jobs require a config file. Here is a manifest for a CronJob that runs a simple demonstration task every minute:

    Run the example CronJob by using this command:

      The output is similar to this:

      1. cronjob.batch/hello created
      1. kubectl get cronjob hello

      The output is similar to this:

      As you can see from the results of the command, the cron job has not scheduled or run any jobs yet. Watch for the job to be created in around one minute:

      1. kubectl get jobs --watch

      The output is similar to this:

      1. NAME               COMPLETIONS   DURATION   AGE
      3. hello-4111706356   0/1           0s         0s

      Now you’ve seen one running job scheduled by the “hello” cron job. You can stop watching the job and view the cron job again to see that it scheduled the job:

      1. kubectl get cronjob hello

      The output is similar to this:

      Now, find the pods that the last scheduled job created and view the standard output of one of the pods.

      Note: The job name is different from the pod name.

      1. # Replace "hello-4111706356" with the job name in your system
      2. pods=$(kubectl get pods --selector=job-name=hello-4111706356 --output=jsonpath={.items[*].metadata.name})

      Show the pod log:

      1. kubectl logs $pods

      The output is similar to this:

      1. Fri Feb 22 11:02:09 UTC 2019

      When you don’t need a cron job any more, delete it with kubectl delete cronjob <cronjob name>: