Timezone error on k8s cronjob

Issue

Found issue on timezone error. Cron expression on CronJob yaml file and pod can have different timezone.

Solution

1. Add tzdata on alphine linux docker image
2. Add environment variable TZ in cronjob’s yaml file

dockerfile example

FROM golang:1.22-alpine3.19 as builder
WORKDIR /src
COPY . /src
RUN go build -C cmd/app -o app
 
FROM golang:1.22-alpine3.19
RUN apk add --no-cache tzdata
COPY --from=builder /src/cmd/app /bin/app
CMD ["/bin/app"]

cronjob yaml example

apiVersion: batch/v1
kind: CronJob
metadata:
  namespace: service
  name: connector
  labels:
    app: connector
spec:
  schedule: "0 7 * * 1-5"
  jobTemplate:
    metadata:
      labels:
        app: connector
    spec:
      template:
        spec:
          containers:
          - name: connector
            image: connector:v1
            # imagePullPolicy: Always
            env: 
              - name: TZ
                value: Asia/Seoul
            command: ["/bin/sh"]
            args:
              - -c
              - 'app --partition=$(($(date +%u) - 1))'
          restartPolicy: OnFailure

docker run example

$ docker run -e TZ=Asia/Seoul connector:v1

Referenced

• dockerfile - How to set timezone inside alpine base docker image? - Stack Overflow