When trying to do a map_reduce call against a replica set, I get the following error
Database command 'mapreduce' failed: (errmsg: 'not master'; ok: '0.0').

Ruby call looks like this
other = {:query => query, :finalize => finalize, :out =>

, :raw => true}
list.map_reduce(map, reduce, other)

Replica set contains 3 nodes.

The driver shoul ddetermine that I am going to do a write in this map_reduce and then use only the master node.