title: Multiple spark streaming contexts on one worker
body: <p>I have single node cluster with 2 CPUs, where I want to run 2 spark streaming jobs.</p>
  
  <p>I also want to use submit mode "cluster". I am using Standalone cluster manager.
  When I submit one application, I see that driver consumes 1 core, and worker 1 core. </p>
  
  <p>Does it mean that there are no cores available for other streaming job? Can 2 streaming jobs reuse executors?</p>
  
  <p>It is totally confusing me, and I don't find it really clear in documentation.</p>
  
  <p>Srdjan </p>