doc-exports/docs/css/umn/css_01_0067.html

Accessing an Elasticsearch Cluster Through the Transport Client

You can use Transport Client to access a CSS cluster with the security mode disabled. For a cluster in security mode, you are advised to use Accessing an Elasticsearch Cluster Through the High Level REST Client.

Precautions

• You are advised to use a Transport Client version that matches the Elasticsearch version. For example, use Transport Client 7.6.2 to access an Elasticsearch 7.6.2 cluster.
• This solution is suitable for clusters that are not using the security mode. Such clusters can only be accessed through private IP addresses.
• Transport Client has been deprecated in Elasticsearch 7.x. You are advised to use High Level Rest Client to access clusters instead.

Prerequisites

• The CSS cluster is available.
• Ensure that the server running Java can communicate with the CSS cluster.
• Install JDK 1.8 on the server. You can download JDK 1.8 from: https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
• Declare Java dependencies.

  7.6.2 indicates the version of the Elasticsearch Java client.

  <dependency>
      <groupId>org.elasticsearch.client</groupId>
      <artifactId>transport</artifactId>
      <version>7.6.2</version>
  </dependency>
  <dependency>
      <groupId>org.elasticsearch</groupId>
      <artifactId>elasticsearch</artifactId>
      <version>7.6.2</version>
  </dependency>

Accessing a Cluster

The following code is an example of using Transport Client to connect to the Elasticsearch cluster and check whether the test index exists.

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import org.elasticsearch.action.ActionFuture; import org.elasticsearch.action.admin.indices.exists.indices.IndicesExistsRequest; import org.elasticsearch.action.admin.indices.exists.indices.IndicesExistsResponse; import org.elasticsearch.client.transport.TransportClient; import org.elasticsearch.common.settings.Settings; import org.elasticsearch.common.transport.TransportAddress; import org.elasticsearch.transport.client.PreBuiltTransportClient; import java.net.InetAddress; import java.net.UnknownHostException; import java.util.concurrent.ExecutionException; public class Main { public static void main(String[] args) throws ExecutionException, InterruptedException, UnknownHostException { String cluster_name = "xxx"; String host1 = "xx.xx.xx.xx"; String host2 = "y.y.y.y"; Settings settings = Settings.builder() .put("client.transport.sniff",false) .put("cluster.name", cluster_name) .build(); TransportClient client = new PreBuiltTransportClient(settings) .addTransportAddress(new TransportAddress(InetAddress.getByName(host1), 9300)) .addTransportAddress(new TransportAddress(InetAddress.getByName(host2), 9300)); IndicesExistsRequest indicesExistsRequest = new IndicesExistsRequest("test"); ActionFuture<IndicesExistsResponse> exists = client.admin().indices().exists(indicesExistsRequest); System.out.println(exists.get().isExists()); } }

In the information above, cluster_name indicates the cluster name, and host1 and host2 indicate the IP addresses of the cluster nodes. You can run the GET _cat/nodes command to obtain the IP addresses of the nodes.

Parent topic: Accessing an Elasticsearch Cluster Using Java