EurekaUpdatingListenerBuilder toBuilder() {
    EurekaUpdatingListenerBuilder result = EurekaUpdatingListener.builder(serviceUrl)
      .homePageUrlPath("/zipkin")
      .healthCheckUrlPath("/health")
      .statusPageUrlPath("/info");
    if (auth != null) result.auth(auth);
    if (appName != null) result.appName(appName);
    if (instanceId != null) result.instanceId(instanceId);
    if (hostname != null) result.hostname(hostname);
    return result;
  }
The hostName property of this instance of zipkin.
zipkin-server/src/main/java/zipkin2/server/internal/eureka/ZipkinEurekaDiscoveryProperties.java