Just Finished looking over the logs you uploaded. I Could not find anything that would say why the MapReduce service fails the smoke test. Out of curiosity here, what do you get in your browser if you log out of the Ambari page, clear the cache, and then log back in? Do you get a page that is at the start of installation, somewhere toward the end, or the Ambari dashboard? If you get the last one could you try going to the ‘Services’ tab and starting up MapReduce?