title: Jenkins: Keep older build running if new build fails to deploy
body: <p>I'm new to jenkins. 
  For that sake I installed the latest version of jenkins i.e. 1.632 on my ubuntu and deployed a war using post build actions in the configuration part. That worked fine for me.</p>
  
  <p>Then I changed a few things in the build making sure that it fails when deployed and it effectively did and I'm not able to access the application die to deployment failure. </p>
  
  <p>But I'm curious here, I have heard that in case of a build failure jenkins makes sure that the previous build remains deployed so that the application is always up and running. Please clarify if I'm wrong or doing anything wrong in my deployment steps.</p>
  
  <p>I did searched a lot about this but couldn't find a valuable answer.</p>