MapR Gateways A MapR gateway mediates one-way communication between a source MapR cluster and a destination cluster. Gateways for Replicating MapR-DB Binary Tables In table replication, MapR-DB replicates updates to tables on source MapR clusters to replicas of those tables on destination MapR clusters. Gateways are services that receive these updates and apply them to the replicas. Gateways for Replicating MapR Streams Streams When replicating streams, MapR Streams replicates messages that are published to a source stream. Gateways are services that receive messages from source streams and publish them in replica streams. Gateways for Indexing MapR-DB Data in Elasticsearch When you index MapR-DB tables in Elasticsearch, MapR-DB replicates table updates to corresponding Elasticsearch types. The MapR-DB tables are in MapR clusters, and the types are in Elasticsearch clusters. Gateways receive table updates and pass them to nodes in Elasticsearch clusters. Configuring MapR Gateways for Binary-Table Replication, Stream Replication, or Indexing Configuring gateways involves deciding where to place them, installing the mapr-gateway package on the nodes that you choose to host the gateways, and specifying to your source MapR cluster where the gateways are located. Configuring MapR Gateways When Combining Table Replication and Indexing There are two basic ways of combining table replication with indexing data in Elasticsearch.