title: how to keep process running after the stage is finished for declarative jenkins pipeline
body: <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>pipeline {
    agent none
    stages {
     stage('Server') {
        agent{
            node {
              label "xxx"
              customWorkspace "/home/xxx/server"
            }
          }
        
        steps {
          sh 'node server.js &amp;'
          //start server
        }
      }
     stage('RunCase') {
        agent{
            node {
              label 'clientServer'
              customWorkspace "/home/xxx/CITest"
            }
          }
  
        steps{
          sh 'start test'
          sh  'run case here'
        }
      }
    }
  
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>I create above Jenkins pipeline. What I want to do is:<br>
  1. start server at server node.<br>
  2. start test at test node.  </p>
  
  <p>However, I found the server process will be closed when second stage start.
  So how to keep server start until my second stage testing work is finished. I try to use <code>&amp;</code>, still not working. It seems it will kill all process I started at first stage. </p>