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In case your application requires time zone switching you can follow this guide.

Prerequisites

To successfully finish this guide, you need the following items.

Time zones in Kubernetes Environment

Default Behaviour in Kubernetes Cluster

Kubernetes clusters inherit the time zone configuration from worker node, so that the default time zone in the Kubernetes cluster is the same as the one in your worker node - it’s controlled by the kernel.

Pod & Container

While it is not trivial to change the time zone at the cluster level, there is an easy way to achieve this at pod and container level.

To achieve this goal, you can follow the scenario below:

Scenario

Start a test container

Start a minimal container e.g. a one with busybox. For example:

apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "100000"

Save this definition file as busybox.yaml and apply it to the cluster:

$ kubectl apply -f busybox.yaml

Wait a moment until the pod deployment has been finished and query the time from the container:

kubectl exec busybox-sleep -it -- date

You would get a similar output, in our example the time zone is UTC:

Wed Feb 26 10:57:53 UTC 2020
Change the time zone in the test container

To change the time zone at pod or container level, do the following:

Share your desired ‘zoneinfo’ file with the pod or container by mounting it from the worker node into the container. The following example shows the change to Berlin local time:

apiVersion: v1
kind: Pod
metadata:
  name: busybox-sleep-2
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "100000"
    volumeMounts:
    - name: timezone-config
      mountPath: /etc/localtime
  volumes:
    - name: timezone-config
      hostPath:
        path: /usr/share/zoneinfo/Europe/Berlin

Basically, it’s the same definition, file but with a volume named timezone-config which set the container’s localtime to your time zone.

Save this definition file as busybox-2.yaml and apply it to the cluster:

$ kubectl apply -f busybox-2.yaml

After waiting a moment until the deployment has been finished query the time from the container:

kubectl exec busybox-sleep-2 -it -- date

You should get an output that shows the Berlin local time:

Wed Feb 26 11:01:04 CET 2020

Summary

We learned the following:

  • How to query time from inside a container
  • How to mount zoneinfo / localtime to the container, so that the time zone changes.

Congratulations! You now know all required steps to change time zone in Kubernetes pods and containers.