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
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.