title: configuring nodes for Jenkins build slaves with docker
body: <p>I've configured my Jenkins master to use docker and I can connect to docker, I've got a simple pipeline to test this:</p>
  
  <pre><code>node ('docker-build-slave') {
      stage ('On slave') {
          sh 'ls -l'
          sh 'uname -a'
      }
  }
  </code></pre>
  
  <p>When I instigate a build and look at whats being written to the console, I get:</p>
  
  <blockquote>
    <p>Started by user chris adkin<br>
    [Pipeline] node<br>
    Still waiting to schedule task<br>
    All nodes of label ‘docker-build-slave’ are offline</p>
  </blockquote>
  
  <p>and it just hangs, I'm wondering if there is something really obvious I ave missed, do I need to create a node for my docker build slaves ?.</p>
  
  <p>If I go onto the machine hosting jenkins, I can see that the build slave container have been started.</p>