title: WDS: Disconnected! loop when running webpack-dev-server simultaneously
body: <p>Here is my use case. 
  Several instances of <strong>webpack-dev-servers, running simultaneously</strong> on shared server everyone is serving content on its one port. </p>
  
  <p>At some point, every site falls into <strong>[WDS] Disconnected! loop</strong>. It's not clear to me where's the breaking point, but obviously, it correlates with the number of WDS instances. </p>
  
  <p>So my question is where's the bottleneck RAM, CPU, too many WebSocket connections? Maybe it is a configuration thing? </p>
  
  <p>Have you ever encountered a similar problem?</p>
  
  <p>Is there a way to fix it? I mean besides working on local machine:)</p>
  
  <ul>
  <li>node: 8.9.1</li>
  <li>webpack: 3.5.5</li>
  <li>webpack-dev-server: 2.7.1</li>
  </ul>