我安装了一个四节点hadoop集群。在hadoopwebui中，我可以看到所有datanodes和namenodes都已启动并正在运行。但是当我跑步的时候 select count(*) from table_name; 在配置单元中，查询被卡住了。

hive> select count(*) from test_hive2;
Query ID = dssbp_20160804124833_ff269da1-6b91-4e46-a1df-460603a5cb98
Total jobs = 1
Launching Job 1 out of 1
Number of reduce tasks determined at compile time: 1
In order to change the average load for a reducer (in bytes):
  set hive.exec.reducers.bytes.per.reducer=<number>
In order to limit the maximum number of reducers:
  set hive.exec.reducers.max=<number>
In order to set a constant number of reducers:
  set mapreduce.job.reduces=<number>

我在datanode节点管理器日志和配置单元日志中不断遇到的错误是：

2016-08-04 12:33:31,474 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: namenode1/172.18.128.24:6005. Already tried 8 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)

我检查过的东西：
1.可以从datanode到name node进行telnet。
2.可以执行hadoop的put和get命令。
3.可以在配置单元中创建表并向其中加载数据。

cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

# ::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

172.18.128.24   namenode1 mycluster
172.18.128.25  namenode2
172.18.128.26  datanode1
172.18.128.27  datanode2

如果有人能提出可能的解决办法，那将大有帮助。
你好，冉扬