The event bus can be configured. It is particularly useful when the event bus is clustered.
Under the hood the event bus uses TCP connections to send and receive messages, so the `link:../../apidocs/io/vertx/core/eventbus/EventBusOptions.html[EventBusOptions]` let you configure all aspects of these TCP connections.
As the event bus acts as a server and client, the configuration is close to `link:../../apidocs/io/vertx/core/net/NetClientOptions.html[NetClientOptions]` and `link:../../apidocs/io/vertx/core/net/NetServerOptions.html[NetServerOptions]`.

[source,java]
----
VertxOptions options = new VertxOptions()
    .setEventBusOptions(new EventBusOptions()
        .setSsl(true)
        .setKeyStoreOptions(new JksOptions().setPath("keystore.jks").setPassword("wibble"))
        .setTrustStoreOptions(new JksOptions().setPath("keystore.jks").setPassword("wibble"))
        .setClientAuth(ClientAuth.REQUIRED)
    );

Vertx
  .clusteredVertx(options)
  .onComplete(res -> {
    if (res.succeeded()) {
      Vertx vertx = res.result();
      EventBus eventBus = vertx.eventBus();
      System.out.println("We now have a clustered event bus: " + eventBus);
    } else {
      System.out.println("Failed: " + res.cause());
    }
  });
----

The previous snippet depicts how you can use SSL connections for the event bus, instead of plain TCP connections.

**WARNING**: to enforce the security in clustered mode, you **must** configure the cluster manager to use encryption or enforce security.
Refer to the documentation of the cluster manager for further details.

The event bus configuration needs to be consistent in all the cluster nodes.

The `link:../../apidocs/io/vertx/core/eventbus/EventBusOptions.html[EventBusOptions]` also lets you specify whether or not the event bus is clustered, the port and host.

When used in containers, you can also configure the public host and port:

[source,java]
----
VertxOptions options = new VertxOptions()
    .setEventBusOptions(new EventBusOptions()
        .setClusterPublicHost("whatever")
        .setClusterPublicPort(1234)
    );

Vertx
  .clusteredVertx(options)
  .onComplete(res -> {
    if (res.succeeded()) {
      Vertx vertx = res.result();
      EventBus eventBus = vertx.eventBus();
      System.out.println("We now have a clustered event bus: " + eventBus);
    } else {
      System.out.println("Failed: " + res.cause());
    }
  });
----