Cron Every 4 Hours — 0 */4 * * *

# /etc/cron.d/my-schedule
MAILTO="admin@example.com"
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

# Runs every 4 hours on the hour
0 */4 * * * www-data /usr/local/bin/my-script.sh >> /var/log/my-script.log 2>&1

apiVersion: batch/v1
kind: CronJob
metadata:
  name: my-scheduled-job
  labels:
    app: my-scheduled-job
spec:
  schedule: "0 */4 * * *"
  timeZone: "UTC"          # requires Kubernetes v1.27+
  concurrencyPolicy: Forbid
  successfulJobsHistoryLimit: 3
  failedJobsHistoryLimit: 1
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: job
            image: alpine:latest
            command:
            - /bin/sh
            - -c
            - echo "Job executed at $(date)"
          restartPolicy: OnFailure

name: Scheduled Workflow

on:
  schedule:
    # Runs every 4 hours on the hour — evaluated strictly in UTC
    - cron: "0 */4 * * *"
  workflow_dispatch: # allow manual trigger

jobs:
  run-job:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Run task
        run: echo "Workflow triggered at $(date)"

@Component
public class ScheduledTask {

    private static final Logger log = LoggerFactory.getLogger(ScheduledTask.class);

    // Runs every 4 hours on the hour
    // Spring uses 6-field cron: sec min hr dom mon dow
    @Scheduled(cron = "0 0 */4 * * *", zone = "UTC")
    public void runTask() {
        log.info("Scheduled job started at: {}", LocalDateTime.now());
        // your business logic here
    }
}

# AWS EventBridge Rule (CloudFormation)
Resources:
  ScheduledRule:
    Type: AWS::Events::Rule
    Properties:
      Name: my-scheduled-rule
      ScheduleExpression: "cron(0 */4 * * ? *)"
      State: ENABLED
      Targets:
        - Arn: !GetAtt MyLambdaFunction.Arn
          Id: LambdaTarget