Transport Client

The TransportClient connects remotely to an Elasticsearch cluster using the transport module. It does not join the cluster, but simply gets one or more initial transport addresses and communicates with them in round robin fashion on each action (though most actions will probably be "two hop" operations).

// on startup

Client client = TransportClient.builder().build()
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("host1"), 9300))
        .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("host2"), 9300));

// on shutdown

client.close();

Note that you have to set the cluster name if you use one different than "elasticsearch":

Settings settings = Settings.settingsBuilder()
        .put("cluster.name", "myClusterName").build();
Client client = TransportClient.builder().settings(settings).build();
//Add transport addresses and do something with the client...

Or using elasticsearch.yml file as shown in Node Client

The client allows sniffing the rest of the cluster, which adds data nodes into its list of machines to use. In this case, note that the IP addresses used will be the ones that the other nodes were started with (the "publish" address). In order to enable it, set the client.transport.sniff to true:

Settings settings = Settings.settingsBuilder()
        .put("client.transport.sniff", true).build();
TransportClient client = TransportClient.builder().settings(settings).build();

Other transport client level settings include: