title: Adding a node to a running replicaset on an existing shard
body: <p>MongoDB shard needs to know about the members of a replicaset. Is the member list discovery dynamic? I mean if we add a node to an existing replicaset which is already configured as a shard on the config servers, does the shard automatically update or do we have do manually update the shard configuration with any new member added to the replica?</p>