Cron – OpenShift: Cronjob is executed in wrong timezone despite master configuration is correct

cronkubernetestimezone

I have a configured a cronjob in OpenShift. Its crontab entry looks like this:

spec:
  schedule: "0 3 * * 1-5"
  jobTemplate:

So it should run at 03:00 in the morning on weekdays. All cluster nodes are configured to use our local timezone, CET, which is UTC+1. This is visible via the date command. OpenShift documentation says that cronjobs are executed via the crontab matching the configured time zone of the master nodes, so i expect the cronjobs to actually run at 03:00 CET.

However, according to the logs, the cronjobs are executed at 04:00 which is 03:00 CET in UTC. The strange part is that oc describe cronjob reveals:

Last Schedule Time:  Mon, 14 Jan 2019 04:00:00 +0100

So, the server actually knows that the cronjob is executed one hour too late.

My question is: Why is the cronjob executed one hour too late, why does the server know about it, and how can i fix this?

Best Answer

CronJobs are controlled by the master-controller.

In Openshift (after ~v3.10), the controllers are run as a pod, defined in /etc/origin/node/pods (at least in our setup).

We had the exact same problem and noticed that the timestamp in controller-logs was one hour off.

This was fixed by adding a mount in /etc/origin/node/pods/controller.yaml

Under volumeMounts:, add: 

   - mountPath: /etc/localtime
      name: localtime

Under volumes:, add: 

  - hostPath:
      path: /etc/localtime
    name: localtime
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