尽管 Hadoop 已启动，但 Map Reduce 作业卡住了

Question

我安装了一个四节点 hadoop cluster.In hadoop Webui 我可以看到所有数据节点和名称节点都已启动并且运行。但是当我在蜂巢中运行 select count(*) from table_name; 时，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>

我在我的数据节点节点管理器日志和配置单元日志中不断收到的错误是：

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.Can 从数据节点远程登录到名称节点。
2.Can 执行 hadoop put 和 get 命令。
3.can 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方案，那将是很大的帮助。

此致，兰詹

Answer 1

我能够解决这个问题，因为资源管理器存在一些问题，并且从数据节点无法连接到 172.18.128.24:6005 这个端口。

尽管 Hadoop 已启动，但 Map Reduce 作业卡住了

Map Reduce job getting stuck though Hadoop is UP

hadoop

hadoop-2.7.2