@Override
  public String toString() {
    return new ToStringBuilder(this)
      .append("nameServiceId", nameServiceId)
      .append("nameNodes", getNameNodes())
      .toString();
  }
NameNodes in this nameservice.
The minimum number of NameNodes for HA is two, but more can be configured.
ambari-server/src/main/java/org/apache/ambari/server/stack/NameService.java