我是一名中国学生，也是Hadoop2.7.1的初学者。如果您能解决我的问题，我将不胜感激。当我最近在伪分布式上运行 hadoop WordCount 示例时，它卡在映射 0% 并减少 0%。
作业的日志如下所示：
……
2017-05-14 16:32:55,939 INFO [main] org.apache.hadoop.yarn.client.api.impl.ContainerManagementProtocolProxy: yarn.client.max-cached-nodemanagers-proxies : 0
2017-05-14 16:32:55,957 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl: job_1494750737018_0001Job Transitioned from INITED to SETUP
2017-05-14 16:32:55,960 INFO [CommitterEvent Processor #0] org.apache.hadoop.mapreduce.v2.app.commit.CommitterEventHandler: Processing the event EventType: JOB_SETUP
2017-05-14 16:32:55,988 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.JobImpl: job_1494750737018_0001Job Transitioned from SETUP to RUNNING
2017-05-14 16:32:56,023 INFO [AsyncDispatcher event handler] org.apache.hadoop.yarn.util.RackResolver: Resolved Gil to /default-rack
2017-05-14 16:32:56,034 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskImpl: task_1494750737018_0001_m_000000 Task Transitioned from NEW to SCHEDULED
2017-05-14 16:32:56,036 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskImpl: task_1494750737018_0001_r_000000 Task Transitioned from NEW to SCHEDULED
2017-05-14 16:32:56,038 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl: attempt_1494750737018_0001_m_000000_0 TaskAttempt Transitioned from NEW to UNASSIGNED
2017-05-14 16:32:56,038 INFO [AsyncDispatcher event handler] org.apache.hadoop.mapreduce.v2.app.job.impl.TaskAttemptImpl: attempt_1494750737018_0001_r_000000_0 TaskAttempt Transitioned from NEW to UNASSIGNED
2017-05-14 16:32:56,039 INFO [Thread-50] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: mapResourceRequest:<memory:1024, vCores:1>
2017-05-14 16:32:56,055 INFO [Thread-50] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: reduceResourceRequest:<memory:1024, vCores:1>
2017-05-14 16:32:56,073 INFO [eventHandlingThread] org.apache.hadoop.mapreduce.jobhistory.JobHistoryEventHandler: Event Writer setup for JobId: job_1494750737018_0001, File: hdfs://localhost:9000/tmp/hadoop-yarn/staging/gil/.staging/job_1494750737018_0001/job_1494750737018_0001_1.jhist
2017-05-14 16:32:56,935 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Before Scheduling: PendingReds:1 ScheduledMaps:1 ScheduledReds:0 AssignedMaps:0 AssignedReds:0 CompletedMaps:0 CompletedReds:0 ContAlloc:0 ContRel:0 HostLocal:0 RackLocal:0
2017-05-14 16:32:56,983 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerRequestor: getResources() for application_1494750737018_0001: ask=3 release= 0 newContainers=0 finishedContainers=0 resourcelimit=<memory:0, vCores:0> knownNMs=1
2017-05-14 16:32:56,984 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:32:56,984 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:32:56,984 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:32:56,985 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:32:57,988 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:32:57,988 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:32:57,988 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:32:57,988 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:32:58,991 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:32:58,991 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:32:58,991 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:32:58,991 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:32:59,994 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:32:59,994 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:32:59,994 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:32:59,994 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:01,000 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:01,000 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:01,001 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:01,001 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:02,003 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:02,003 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:02,004 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:02,004 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:03,006 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:03,007 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:03,007 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:03,007 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:04,009 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:04,010 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:04,010 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:04,010 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:05,014 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:05,014 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:05,014 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:05,014 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:06,019 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:06,019 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:06,020 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:06,020 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:07,022 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:07,022 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:07,022 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:07,022 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:08,025 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:08,025 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:08,025 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:08,025 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
2017-05-14 16:33:09,027 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Ramping down all scheduled reduces:0
2017-05-14 16:33:09,028 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Going to preempt 1 due to lack of space for maps
2017-05-14 16:33:09,028 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Recalculating schedule, headroom=<memory:0, vCores:0>
2017-05-14 16:33:09,028 INFO [RMCommunicator Allocator] org.apache.hadoop.mapreduce.v2.app.rm.RMContainerAllocator: Reduce slow start threshold not met. completedMapsForReduceSlowstart 1
……
……
……
然后它一直在回收。
这是我的纱线网站.xml：
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
<property>
<name>yarn.nodemanager.env-whitelist</name>
<value>JAVA_HOME,HADOOP_COMMON_HOME,HADOOP_HDFS_HOME,HADOOP_CONF_DIR,HADOOP_YARN_HOME,HADOOP_MAPRED_HOME</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>2200</value>
</property>
<property>
<name>yarn.scheduler.minimum-allocation-mb</name>
<value>500</value>
</property>
<property>
<name>yarn.resourcemanager.hostname</name>
<value>localhost</value>
</property>
</configuration>
这是我的地图网站.xml
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
<property>
<name>mapreduce.jobhistory.address</name>
<value>127.0.0.1:10020</value>
</property>
<property>
<name>mapreduce.jobhistory.webapp.address</name>
<value>127.0.0.1:19888</value>
</property>
<property>
<name>mapred.job.tracker</name>
<value>127.0.0.1:9001</value>
</property>
</configuration>
这是logs/hadoop-*.out：
ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 15001
max locked memory (kbytes, -l) 64
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 15001
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
我怀疑它与我的硬盘空间有关，我的硬盘空间只剩下5.6GB。因为当我将其从 3.xGB 清理到 5.6GB 时，它卡在接受状态并且不会运行。但是在我稍微清理它之后，它开始运行，但坚持在地图 0% 减少 0%。
此外，当我执行一个蜂巢时，它将创建一个地图减少作业，例如INSERT INTO xx VALUES(xxx); 它还将停留在地图 0% 减少 0%。
对我来说一些环境：
乌班图 14.04 64
Hadoop-2.7.1
爪哇-8
我该怎么办？
谢谢！
使用默认的xml设置，它将解决您的问题，因为您正在限制集群资源，有可能错过计算，"默认">一词意味着不定义任何与内存相关的规范在您的情况下：删除
<property>
<name>yarn.nodemanager.resource.memory-mb</name>
<value>2200</value>
</property>
<property>
<name>yarn.scheduler.minimum-allocation-mb</name>
<value>500</value>
</property>
然后尝试 ，如果有效，请查看 https://hortonworks.com/blog/how-to-plan-and-configure-yarn-in-hdp-2-0/链接以更好地了解如何设置群集资源。
这对我来说是：1. 使用主机名称定义其/etc/hosts 中的所有群集节点。2. 在所有设置文件(hdfs-site、yarn-site、mapred-site(中，使用定义的名称设置主节点。
我认为在带有主机名的/etc/hosts 中使用不同的名称可能是导致此失败的原因。