Mar 20 13:57:38 stats-worker-3290520465-k9rtf stats-worker-prod: W, [2018-03-20T13:57:38.375521 #6]  WARN -- : document update failed with: end of file reached
Mar 20 13:57:38 stats-worker-3290520465-k9rtf stats-worker-prod: W, [2018-03-20T13:57:38.381792 #6]  WARN -- : document update failed with: end of file reached
Mar 20 13:57:39 stats-worker-3290520465-k9rtf stats-worker-prod: W, [2018-03-20T13:57:38.981986 #6]  WARN -- : document update failed with: end of file reached
Mar 20 13:58:08 stats-worker-3290520465-k9rtf stats-worker-prod: E, [2018-03-20T13:58:08.278147 #6] ERROR -- : worker failed with: No server is available matching preference: #<Mongo::ServerSelector::Primary:0x350056961260 tag_sets=[] max_staleness=nil> using server_selection_timeout=30 and local_threshold=0.015 ["/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/server_selector/selectable.rb:115:in `select_server'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/cluster.rb:246:in `next_primary'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/retryable.rb:150:in `legacy_write_with_retry'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/retryable.rb:103:in `write_with_retry'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/collection/view/writable.rb:295:in `block in update_one'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/collection/view.rb:204:in `block in with_session'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/client.rb:485:in `with_session'"
Mar 20 13:58:08 stats-worker-3290520465-k9rtf stats-worker-prod: W, [2018-03-20T13:58:08.374091 #6]  WARN -- : document update failed with: No server is available matching preference: #<Mongo::ServerSelector::Primary:0x350056961260 tag_sets=[] max_staleness=nil> using server_selection_timeout=30 and local_threshold=0.015
Mar 20 13:58:09 stats-worker-3290520465-k9rtf stats-worker-prod: E, [2018-03-20T13:58:09.373729 #6] ERROR -- : worker failed with: No server is available matching preference: #<Mongo::ServerSelector::Primary:0x350056961260 tag_sets=[] max_staleness=nil> using server_selection_timeout=30 and local_threshold=0.015 ["/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/server_selector/selectable.rb:115:in `select_server'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/cluster.rb:246:in `next_primary'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/retryable.rb:150:in `legacy_write_with_retry'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/retryable.rb:103:in `write_with_retry'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/collection/view/writable.rb:295:in `block in update_one'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/collection/view.rb:204:in `block in with_session'",
 "/usr/local/bundle/gems/mongo-2.5.0/lib/mongo/client.rb:485:in `with_session'"