title: Does single hive application(job) spawn multiple yarn applications?
body: <p>Does a single HIVE query that gets submitted to Yarn creates multiple jobs (i.e. multiple YARN applications) ? Here I treat job and application to be the same think in YARN context.</p>
  
  <p>From what I understand -- Yarn creates an Application Master (AM) per 'application'. So here that single HIVE query can be treated as an 'application'. So, the Resource Manager will create container on some node and start AM in that container. That container in turn may create multiple 'tasks' (not applications) i.e. mappers and reducers within other containers reserved for that AM (on the same or different node -- this is immaterial here). Now the collection of all these Application Masters are engaged in solving that single HIVE query that is submitted to YARN. In fact that's why we say that AM is per application. Since we submitted just one HIVE query, from YARN point of view there is only one application. So when I fire the below YARN command, it should show me just one application running:-</p>
  
  <pre><code>yarn application -list
  </code></pre>
  
  <p>Is this understanding correct? Or that if we have several mappers and reducers spawned for that one HIVE query, multiple YARN applications are invoked?</p>