} finally {
        monitor.leave();
      }
    }

    void awaitHealthy(long timeout, TimeUnit unit) throws TimeoutException {
      monitor.enter();
      try {
        if (!monitor.waitForUninterruptibly(awaitHealthGuard, timeout, unit)) {
          throw new TimeoutException(
              "Timeout waiting for the services to become healthy. The "
                  + "following services have not started: "