title: Amazon EMR: Only start new scheduled job if previous job has finished
body: <p>I have a AWS EMR cluster job which runs every 2 hours. I have set up a schedule using cloudWatch job to run every two hours.</p>
  <p>But sometimes the next job (which runs after 2 hour from previous one) starts when previous one is not finished as it sometimes take more than 2 hours to completed depending on data to be processed.</p>
  <p>I need some configuration by which I could prevent next job to be started if previous job is running.
  I tried but couldn't found any set up. Can anyone knows how to do that please?</p>