How to schedule a cronjob which executes a kubectl command?

Question

How to schedule a cronjob which executes a kubectl command?

I would like to run the following kubectl command every 5 minutes:

kubectl patch deployme         


        

Answer 1

You need to make the CronJob's container to download the cluster configuration so then you can run kubectl commands against it. Here is an example:

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: drupal-cron
spec:
  schedule: "*/5 * * * *"
  concurrencyPolicy: Forbid
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: drupal-cron
              image: juampynr/digital-ocean-cronjob:latest
              env:
                - name: DIGITALOCEAN_ACCESS_TOKEN
                  valueFrom:
                    secretKeyRef:
                      name: api
                      key: key
              command: ["/bin/bash","-c"]
              args:
                - doctl kubernetes cluster kubeconfig save drupster;
                  POD_NAME=$(kubectl get pods -l tier=frontend -o=jsonpath='{.items[0].metadata.name}');
                  kubectl exec $POD_NAME -c drupal -- vendor/bin/drush core:cron;
          restartPolicy: OnFailure

I posted an answer describing how I did this in a different thread: https://stackoverflow.com/a/62321138/1120652