Question

我在cloudera cdh4上运行一个冠层群集作业（使用mahout）。要聚类的内容大约有1m条记录（每条记录的大小不到1k）。整个hadoop环境（包括所有节点）都在带有4G内存的虚拟机中运行。默认安装cdh4。运行作业时出现以下异常。

根据异常，它看起来作业客户端应该需要更高的jvm堆大小。但是，cloudera管理器中的jvm堆大小有很多配置选项。我将“以字节为单位的客户端Java堆大小”从256MiB更改为512MiB。但是，它并没有改善。

有关设置这些堆大小选项的任何提示/技巧吗？

13/07/03 17:12:45 INFO input.FileInputFormat: Total input paths to process : 1
13/07/03 17:12:46 INFO mapred.JobClient: Running job: job_201307031710_0001
13/07/03 17:12:47 INFO mapred.JobClient:  map 0% reduce 0%
13/07/03 17:13:06 INFO mapred.JobClient:  map 1% reduce 0%
13/07/03 17:13:27 INFO mapred.JobClient:  map 2% reduce 0%
13/07/03 17:14:01 INFO mapred.JobClient:  map 3% reduce 0%
13/07/03 17:14:50 INFO mapred.JobClient:  map 4% reduce 0%
13/07/03 17:15:50 INFO mapred.JobClient:  map 5% reduce 0%
13/07/03 17:17:06 INFO mapred.JobClient:  map 6% reduce 0%
13/07/03 17:18:44 INFO mapred.JobClient:  map 7% reduce 0%
13/07/03 17:20:24 INFO mapred.JobClient:  map 8% reduce 0%
13/07/03 17:22:20 INFO mapred.JobClient:  map 9% reduce 0%
13/07/03 17:25:00 INFO mapred.JobClient:  map 10% reduce 0%
13/07/03 17:28:08 INFO mapred.JobClient:  map 11% reduce 0%
13/07/03 17:31:46 INFO mapred.JobClient:  map 12% reduce 0%
13/07/03 17:35:57 INFO mapred.JobClient:  map 13% reduce 0%
13/07/03 17:40:52 INFO mapred.JobClient:  map 14% reduce 0%
13/07/03 17:46:55 INFO mapred.JobClient:  map 15% reduce 0%
13/07/03 17:55:02 INFO mapred.JobClient:  map 16% reduce 0%
13/07/03 18:08:42 INFO mapred.JobClient:  map 17% reduce 0%
13/07/03 18:59:11 INFO mapred.JobClient:  map 8% reduce 0%
13/07/03 18:59:13 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000001_0, Status : FAILED
Error: GC overhead limit exceeded
13/07/03 18:59:23 INFO mapred.JobClient:  map 9% reduce 0%
13/07/03 19:00:09 INFO mapred.JobClient:  map 10% reduce 0%
13/07/03 19:01:49 INFO mapred.JobClient:  map 11% reduce 0%
13/07/03 19:04:25 INFO mapred.JobClient:  map 12% reduce 0%
13/07/03 19:07:48 INFO mapred.JobClient:  map 13% reduce 0%
13/07/03 19:12:48 INFO mapred.JobClient:  map 14% reduce 0%
13/07/03 19:19:46 INFO mapred.JobClient:  map 15% reduce 0%
13/07/03 19:29:05 INFO mapred.JobClient:  map 16% reduce 0%
13/07/03 19:43:43 INFO mapred.JobClient:  map 17% reduce 0%
13/07/03 20:49:36 INFO mapred.JobClient:  map 8% reduce 0%
13/07/03 20:49:38 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000001_1, Status : FAILED
Error: GC overhead limit exceeded
13/07/03 20:49:48 INFO mapred.JobClient:  map 9% reduce 0%
13/07/03 20:50:31 INFO mapred.JobClient:  map 10% reduce 0%
13/07/03 20:52:08 INFO mapred.JobClient:  map 11% reduce 0%
13/07/03 20:54:38 INFO mapred.JobClient:  map 12% reduce 0%
13/07/03 20:58:01 INFO mapred.JobClient:  map 13% reduce 0%
13/07/03 21:03:01 INFO mapred.JobClient:  map 14% reduce 0%
13/07/03 21:10:10 INFO mapred.JobClient:  map 15% reduce 0%
13/07/03 21:19:54 INFO mapred.JobClient:  map 16% reduce 0%
13/07/03 21:31:35 INFO mapred.JobClient:  map 8% reduce 0%
13/07/03 21:31:37 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000000_0, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:250)
Caused by: java.io.IOException: Task process exit with nonzero status of 65.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:237)

13/07/03 21:32:09 INFO mapred.JobClient:  map 9% reduce 0%
13/07/03 21:33:31 INFO mapred.JobClient:  map 10% reduce 0%
13/07/03 21:35:42 INFO mapred.JobClient:  map 11% reduce 0%
13/07/03 21:38:41 INFO mapred.JobClient:  map 12% reduce 0%
13/07/03 21:42:27 INFO mapred.JobClient:  map 13% reduce 0%
13/07/03 21:48:20 INFO mapred.JobClient:  map 14% reduce 0%
13/07/03 21:56:12 INFO mapred.JobClient:  map 15% reduce 0%
13/07/03 22:07:20 INFO mapred.JobClient:  map 16% reduce 0%
13/07/03 22:26:36 INFO mapred.JobClient:  map 17% reduce 0%
13/07/03 23:35:30 INFO mapred.JobClient:  map 8% reduce 0%
13/07/03 23:35:32 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000000_1, Status : FAILED
Error: GC overhead limit exceeded
13/07/03 23:35:42 INFO mapred.JobClient:  map 9% reduce 0%
13/07/03 23:36:16 INFO mapred.JobClient:  map 10% reduce 0%
13/07/03 23:38:01 INFO mapred.JobClient:  map 11% reduce 0%
13/07/03 23:40:47 INFO mapred.JobClient:  map 12% reduce 0%
13/07/03 23:44:44 INFO mapred.JobClient:  map 13% reduce 0%
13/07/03 23:50:42 INFO mapred.JobClient:  map 14% reduce 0%
13/07/03 23:58:58 INFO mapred.JobClient:  map 15% reduce 0%
13/07/04 00:10:22 INFO mapred.JobClient:  map 16% reduce 0%
13/07/04 00:21:38 INFO mapred.JobClient:  map 7% reduce 0%
13/07/04 00:21:40 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000001_2, Status : FAILED
java.lang.Throwable: Child Error
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:250)
Caused by: java.io.IOException: Task process exit with nonzero status of 65.
    at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:237)

13/07/04 00:21:50 INFO mapred.JobClient:  map 8% reduce 0%
13/07/04 00:22:27 INFO mapred.JobClient:  map 9% reduce 0%
13/07/04 00:23:52 INFO mapred.JobClient:  map 10% reduce 0%
13/07/04 00:26:00 INFO mapred.JobClient:  map 11% reduce 0%
13/07/04 00:28:47 INFO mapred.JobClient:  map 12% reduce 0%
13/07/04 00:32:17 INFO mapred.JobClient:  map 13% reduce 0%
13/07/04 00:37:34 INFO mapred.JobClient:  map 14% reduce 0%
13/07/04 00:44:30 INFO mapred.JobClient:  map 15% reduce 0%
13/07/04 00:54:28 INFO mapred.JobClient:  map 16% reduce 0%
13/07/04 01:16:30 INFO mapred.JobClient:  map 17% reduce 0%
13/07/04 01:32:05 INFO mapred.JobClient:  map 8% reduce 0%
13/07/04 01:32:08 INFO mapred.JobClient: Task Id : attempt_201307031710_0001_m_000000_2, Status : FAILED
Error: GC overhead limit exceeded
13/07/04 01:32:21 INFO mapred.JobClient:  map 9% reduce 0%
13/07/04 01:33:26 INFO mapred.JobClient:  map 10% reduce 0%
13/07/04 01:35:37 INFO mapred.JobClient:  map 11% reduce 0%
13/07/04 01:38:48 INFO mapred.JobClient:  map 12% reduce 0%
13/07/04 01:43:06 INFO mapred.JobClient:  map 13% reduce 0%
13/07/04 01:49:58 INFO mapred.JobClient:  map 14% reduce 0%
13/07/04 01:59:07 INFO mapred.JobClient:  map 15% reduce 0%
13/07/04 02:12:00 INFO mapred.JobClient:  map 16% reduce 0%
13/07/04 02:37:56 INFO mapred.JobClient:  map 17% reduce 0%
13/07/04 03:31:55 INFO mapred.JobClient:  map 8% reduce 0%
13/07/04 03:32:00 INFO mapred.JobClient: Job complete: job_201307031710_0001
13/07/04 03:32:00 INFO mapred.JobClient: Counters: 7
13/07/04 03:32:00 INFO mapred.JobClient:   Job Counters 
13/07/04 03:32:00 INFO mapred.JobClient:     Failed map tasks=1
13/07/04 03:32:00 INFO mapred.JobClient:     Launched map tasks=8
13/07/04 03:32:00 INFO mapred.JobClient:     Data-local map tasks=8
13/07/04 03:32:00 INFO mapred.JobClient:     Total time spent by all maps in occupied slots (ms)=11443502
13/07/04 03:32:00 INFO mapred.JobClient:     Total time spent by all reduces in occupied slots (ms)=0
13/07/04 03:32:00 INFO mapred.JobClient:     Total time spent by all maps waiting after reserving slots (ms)=0
13/07/04 03:32:00 INFO mapred.JobClient:     Total time spent by all reduces waiting after reserving slots (ms)=0
Exception in thread "main" java.lang.RuntimeException: java.lang.InterruptedException: Canopy Job failed processing vector

Answer 1

Mahout工作非常耗费内存。我不知道映射器或缩减器是否是罪魁祸首，但是，无论哪种方式，你都必须告诉Hadoop给它们更多的RAM。 “GC Overhead Limit Exceeded”只是一种说“内存不足”的方式 - 意味着JVM放弃了尝试回收最后0.01％的可用内存。

你如何设置它确实有点复杂，因为有几个属性并且它们在Hadoop 2中发生了变化.CDH4可以支持Hadoop 1或2 - 你正在使用哪一个？

如果我不得不猜测：将mapreduce.child.java.opts设为-Xmx1g。但正确的答案实际上取决于您的版本和数据。

Answer 2

您需要更改Hadoop的内存设置，因为为Hadoop分配的内存不足以满足您正在运行的作业要求，尝试增加堆内存并验证，由于过度使用内存操作系统可能会被查杀由于哪个工作失败而导致的流程。

cloudera hadoop mapreduce作业GC开销限制超出错误

2 个答案: