title: Does a playbook call a number of plays?
body: <p>We have started to write some Ansible scripts and are wondering how to structure out code. 
  The problem we are trying to answer is...  what is a play vs playbook vs roles
  currently we have </p>
  
  <pre><code>-group_vars/...(a bunch of group vars)
  -Playbooks/java/java_stack.yml
                  java_app.yml
  
  -roles/java_roles/...(a bunch of roles used in the two plays above).
  </code></pre>
  
  <p>I was under the impression that there is another level that we could call. (a playbook). where it is a group of plays. So we could call from one playbook, a number of plays. 
  Exmaple playbook. (install java with apps). 
  This would run <code>playbooks/java/java_stack.yml</code> once and then run <code>java_app</code>, say 3 times (with different parameters) to install what is needed.</p>
  
  <p>Or is this something that really isn't designed in ansible and are playbooks just a group of roles and tasks. </p>