Another thing worth mentioning about Impala bulk inserts into Kudu: you may benefit from the /* +noshuffle,noclustered */ insert hint, or from setting a MEM_LIMIT, as outlined here: https://www.cloudera.com/documentation/enterprise/6/6.2/topics/impala_hints.html ... View more

You don't need to take down the other masters, but need to establish a maintenance window (no DDLs) to ensure the table metadata is consistent between followers and the leader. If it is hard in production, alternative is to ensure the master to be taken down is not the leader (to avoid lose data). ... View more