title: In a containerized cluster, should mongodb servers be running on a worker or a core service?
body: <p>I'm trying to implement an architecture that's similar to the coreos's production architecture (shown below)</p>
  
  <p><img src="https://i.stack.imgur.com/01wrE.png" alt="enter image description here"></p>
  
  <p>Should I run the database as a central service or one or more of the workers?</p>
  
  <p>I figured the database needs some kind of replication, which makes me think that putting it in the worker cluster makes more sense, but I'm just not sure.</p>