title: Pass information between two Jenkins jobs in a Pipeline
body: <p>I want to migrate an existing job to <a href="https://jenkins.io/doc/pipeline/" rel="nofollow">Jenkins Pipeline</a> and this process I try to migrate the different plugins attached to this job to use the new syntax.</p>
  
  <p>However, not all plugins provide a corresponding wrapper syntax.</p>
  
  <p>In the current case, I want to allocate three separate ports (embedded DB, container, and process engine) so that the build can run independently from other builds on the same machine. In the classic Jenkins job, we could use the <a href="https://wiki.jenkins-ci.org/display/JENKINS/Port+Allocator+Plugin" rel="nofollow">Port Allocator Plugin</a>, but it's not (<a href="https://issues.jenkins-ci.org/browse/JENKINS-31449" rel="nofollow">yet</a>) available via Pipeline Syntax.</p>
  
  <p>My idea is to trigger a classic build that uses the port allocator plugin and returns the free ports that I can then use in a later build to start up the required services.</p>
  
  <pre>
  node {
      stage("Allocate Ports") {
          build job: "allocate-port", parameters: [ // &lt;- the classic build
              string(name: "name1", value: "PORT_DB"),
              string(name: "name2", value: "PORT_CONTAINER"),
              string(name: "name3", value: "PORT_ENGINE")
          ]
      }
      stage("Integration Tests") {
          sh """
             run-test \
              -db=${PORT_DB} \
              -container=${PORT_CONTAINER} \
              -engine=${PORT_ENGINE}
          """
      }
  }
  </pre>
  
  <p>Is there a good way to store the results from the <em>allocate-port</em> build and return it to the enclosing pipeline?</p>