title: node.js app deployment using pm2 without downtime
body: <p>There are tons of tutorial how to develop chat application using socket.io and node.js and no doubt event driven advantage of node has the advantage of doing chat application. But recently this thought came into my mind, how can I sustain my chat app when I deploy the app? imagine there are thousand of users are actively chatting in it.</p>
  
  <p>in this article <a href="https://futurestud.io/tutorials/pm2-cluster-mode-and-zero-downtime-restarts" rel="nofollow noreferrer">https://futurestud.io/tutorials/pm2-cluster-mode-and-zero-downtime-restarts</a> clearly state that cluster technqiue required extra cares, hmm is there any way to tackle this issue?</p>