code: @Override
    public void registerHost(final String host, final String id) {
      final ZooKeeperClient client = provider.get("registerHost");
      try {
        ZooKeeperRegistrarUtil.registerHost(client, Paths.configHostId(host), host, id);
      } catch (Exception e) {
        throw new HeliosRuntimeException("registering host " + host + " failed", e);
      }
    }
docs: Registers a host into ZooKeeper.  The {@code id} is initially generated randomly by the Agent
  and persisted on disk.  This way, in the event that you have two agents attempting to register
  with the same value of @{code host}, the first one will win.