title: Distributed Task Scheduling, Job Queue
body: <p>I have to email a certain task notification that needs to be sent out to users who are expecting it every 6 hours. So I have used node-cron to schedule a job on my server which wakes up every 30 min to check if any users havent responded to their emails, tracked using mysql db with updated_at col. Works fine!</p>
  
  <p>But now I have to make it work in a distributed setting. Using Elastic Beanstalk with 1-4 micro ec2 instances. I dont want to add any other db/storage/queue other than what I have (MySQL). </p>
  
  <ul>
  <li>Can someone lay out the steps to do it in conjunction with node-cron. (Ensuring a certain task is performed once, I dont want to send notifications before my 6 hour period)</li>
  <li>OR do we some other library that can do this in mysql ensuring that a task is done only once</li>
  <li>Rather than 30 min period can I do the task when load on my server or db is not strained.</li>
  <li>Is there a way to do it without using db(and multiple instances), since scheduling for work in every 30 mins works fine!</li>
  </ul>
  
  <p>To add, my api server and the worker are same.</p>