In the old age of a single machine, we use /etc/crontab to schedule the job. But in the new age of the distributed system, especially Kubernetes, what should we use?

The first choice in my mind is CronJob, like this one:

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: hello
spec:
  schedule: "*/1 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: hello
            image: busybox
            imagePullPolicy: IfNotPresent
            args:
            - /bin/sh
            - -c
            - date; echo Hello from the Kubernetes cluster
          restartPolicy: OnFailure

Then my colleague recommends the CronWorkflow (need at least v2.5 of Argo) to me. Its configuration seems not very different:

apiVersion: argoproj.io/v1alpha1
kind: CronWorkflow
metadata:
  name: test-cron-wf
spec:
  schedule: "* * * * *"
  concurrencyPolicy: "Replace"
  startingDeadlineSeconds: 0
  workflowSpec:
    entrypoint: whalesay
    templates:
    - name: whalesay
      container:
        image: alpine:3.6
        command: [sh, -c]
        args: ["date; sleep 90"]

But CronWorkflow have a advantage over CronJob: the UI. We can use Web UI to access and manage different types of workflows:

And the UI also makes the accessing of pod log very easy.

Related Posts