Hadoop单机版安装
以前对Hadoop有过一点了解，但没有深入，现在越来越感觉这东西挺有意思的，打算学习下，前两天买了两本Hadoop相关的书，先粗略的翻了下，今天就动手先把环境搭起来。
环境：centos6.2,jdk7_u45,hadoop2.2.0
下载，解压过程就不说了，直接环境配置（包括JAVA_HOME的配置，以及HADOOP_HOME的环境变量配置，都略过了）。参考文档http://hadoop.apache.org/docs/r2.2.0/hadoop-project-dist/hadoop-common/SingleCluster.html
1，修改hadoop-env.sh中修改JAVA_HOME
2，修改core-site.xml配置文件
hadoop.tmp.dir
/data/hadoop/tmp
fs.defaultFS
hdfs://localhost:9000
true
3，修改hdfs-site.xml配置文件
dfs.namenode.name.dir file:///data/hadoop/dfs/name true dfs.datanode.data.dir file:///data/hadoop/dfs/data true dfs.replication 1 dfs.permissions.enabled false 4，复制mapred-site.xml.template成mapred-site.xml，修改mapred-site.xml
cp mapred-site.xml.template mapred-site.xml
vi mapred-site.xml
mapreduce.framework.name
yarn
5,修改yarn-site.xml配置文件
yarn.resourcemanager.hostname
localhost
hostanem of RM
yarn.resourcemanager.resource-tracker.address
localhost:5274
host is the hostname of the resource manager and
port is the port on which the NodeManagers contact the Resource Manager.
yarn.resourcemanager.scheduler.address
localhost:5273
host is the hostname of the resourcemanager and port is the port
on which the Applications in the cluster talk to the Resource Manager.
yarn.resourcemanager.scheduler.class
org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler
In case you do not want to use the default scheduler
yarn.resourcemanager.address
localhost:5271
the host is the hostname of the ResourceManager and the port is the port on
which the clients can talk to the Resource Manager.
yarn.nodemanager.local-dirs
the local directories used by the nodemanager
yarn.nodemanager.address
localhost:5272
the nodemanagers bind to this port
yarn.nodemanager.resource.memory-mb
10240
the amount of memory on the NodeManager in GB
yarn.nodemanager.remote-app-log-dir
/app-logs
directory on hdfs where the application logs are moved to
yarn.nodemanager.log-dirs
the directories used by Nodemanagers as log directories
yarn.nodemanager.aux-services
mapreduce_shuffle
shuffle service that needs to be set for Map Reduce to run
到此为止，hadoop单机版配置已经完成。
1）接下来我们先格式化namenode,然后启动namenode
hadoop namenode –format./hadoop-daemon.sh start namenode2）接着启动hdfs datanode
./hadoop-daemon.sh start datanode还可以在命令行数据Jps查看是否有结果
3)继续启动yarn
yarn-daemon.sh start resourcemanager
yarn-daemon.sh start nodemanager判断启动成功与否方法同上面一致。
最后进入hadoop-2.2.0\share\hadoop\mapreduce录入中，测试运行
hadoop jar hadoop-mapreduce-examples-2.2.0.jar randomwriter out查看运行是否成功
安装中的错误
016-09-29 19:08:11,085 INFO org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Transitioned to standby state
2016-09-29 19:08:11,085 FATAL org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: Error starting ResourceManager
org.apache.hadoop.yarn.exceptions.YarnRuntimeException: Could not instantiate Scheduler: org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler
at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.main(ResourceManager.java:1103)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler
at java.lang.Class.forName(Class.java:191)
at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.createScheduler(ResourceManager.java:264)
... 6 more
2016-09-29 19:08:11,103 INFO org.apache.hadoop.yarn.server.resourcemanager.ResourceManager: SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down ResourceManager at localhost/127.0.0.1
***********************************************************/
在hadoop-2.5.2版本上，已经把 yarn-site注释掉
yarn.resourcemanager.scheduler.class 这个属性。用默认的scheduler即可解决掉。