eclipse-vertx/vert.x · error · IllegalArgumentException

clusterPort p must be in range 0 <= p <= 65535

Error message

clusterPort p must be in range 0 <= p <= 65535

What it means

Configuration validation in EventBusOptions.setPort: the clustered event bus port must lie in the valid TCP port range 0-65535. Ports outside this range cannot be bound and are rejected by the setter (note the message says 'clusterPort' because this value backs the --cluster-port option).

Source

Thrown at vertx-core/src/main/java/io/vertx/core/eventbus/EventBusOptions.java:268

  /**
   * @return the port, which can be configured from the {@link #setPort(int)}, or
   * using the {@code --cluster-port} command line option.
   * @see NetServerOptions#getPort()
   */
  public int getPort() {
    return port;
  }

  /**
   * Sets the port.
   *
   * @param port the port
   * @return a reference to this, so the API can be used fluently
   * @see NetServerOptions#setPort(int)
   */
  public EventBusOptions setPort(int port) {
    if (port < 0 || port > 65535) {
      throw new IllegalArgumentException("clusterPort p must be in range 0 <= p <= 65535");
    }
    this.port = port;
    return this;
  }


  /**
   * @return the value of reconnect attempts
   * @see NetClientOptions#getReconnectAttempts()
   */
  public int getReconnectAttempts() {
    return reconnectAttempts;
  }


  /**
   * Sets the value of reconnect attempts.
   *

View on GitHub (pinned to fb308bd8c3)

Solutions

1. Choose a port in 0..65535 (0 lets the system pick an ephemeral port)
2. Validate externally supplied cluster port configuration before applying it

When it happens

Trigger: Thrown at vertx-core/src/main/java/io/vertx/core/eventbus/EventBusOptions.java:268 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of eclipse-vertx/vert.x@fb308bd8c3 (2026-09-06). Data as JSON: /api/errors/2e5ea13d61c5dbc9. Report an issue: GitHub.