code: @Override
    public HostStatus getHostStatus(final String host) {
      final ZooKeeperClient client = provider.get("getHostStatus");
  
      if (!ZooKeeperRegistrarUtil.isHostRegistered(client, host)) {
        log.warn("Host {} isn't registered in ZooKeeper.", host);
        return null;
      }
  
      final boolean up = checkHostUp(client, host);
      final HostInfo hostInfo = getHostInfo(client, host);
      final AgentInfo agentInfo = getAgentInfo(client, host);
      final Map<JobId, Deployment> tasks = getTasks(client, host);
      final Map<JobId, TaskStatus> statuses = getTaskStatuses(client, host);
      final Map<String, String> environment = getEnvironment(client, host);
      final Map<String, String> labels = getLabels(client, host);
  
      return HostStatus.newBuilder()
          .setJobs(tasks)
          .setStatuses(fromNullable(statuses).or(EMPTY_STATUSES))
          .setHostInfo(hostInfo)
          .setAgentInfo(agentInfo)
          .setStatus(up ? UP : DOWN)
          .setEnvironment(environment)
          .setLabels(labels)
          .build();
    }
docs: Returns the current status of the host named by {@code host}.