Riaknostic caches data about the members of the ring here: https://github.com/basho/riaknostic/blob/2.0.0/src/riaknostic_node.erl#L192-L208 When a node leaves, this needs to be invalidated. There is a mailing list thread with details: http://lists.basho.com/pipermail/riak-users_lists.basho.com/2014-September/016000.html