配置环境
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本文档安装hadoop集群环境，一个master作为namenode节点，一个slave作为datanode节点：
(1) master：
os: CentOS release 6.5 (Final)
ip: 172.16.101.58
user：root
hadoop-2.9.0.tar.gz
(2) slave：
os: CentOS release 6.5 (Final)
ip: 172.16.101.59
user：root
hadoop-2.9.0.tar.gz
前提条件
(1) master和slave都安装好java环境，并配置好环境变量；
(2)master节点解压好hadoop-2.9.0.tar.gz，并配置好环境变量；
(3)本篇文档使用的是root用户安装，所以需要master上的root用户可以ssh无密码使用root用户登录slave节点；
配置集群文件
在 master节点上执行（本文档先在master节点上配置文件，然后通过scp拷贝到其他slave节点）
（1）slaves文件：将作为 DataNode 的主机名或者ip写入该文件，每行一个，默认为 localhost，所以在伪分布式配置时，节点既作为 NameNode 也作为 DataNode。
[root@sht-sgmhadoopdn-01 hadoop]# cat slaves
172.16.101.59
（2）文件core-site.xml
[root@sht-sgmhadoopdn-01 hadoop]#cat /usr/local/hadoop-2.9.0/etc/hadoop/core-site.xml
（3）文件hdfs-site.xml
[root@sht-sgmhadoopdn-01 hadoop]# cat /usr/local/hadoop-2.9.0/etc/hadoop/hdfs-site.xml
（4）文件mapred-site.xml
[root@sht-sgmhadoopdn-01 hadoop]# cat /usr/local/hadoop-2.9.0/etc/hadoop/mapred-site.xml
（5）文件yarn-site.xml
[root@sht-sgmhadoopdn-01 hadoop]# cat /usr/local/hadoop-2.9.0/etc/yarn-site.xml
配置好后，将 Master上的 /usr/local/hadoop-2.9.0文件复制到各个节点上。因为之前有跑过伪分布式模式，建议在切换到集群模式前先删除之前的临时文件。
[root@sht-sgmhadoopdn-01 local]# rm -rf ./hadoop-2.9.0/tmp
[root@sht-sgmhadoopdn-01 local]# rm -rf ./hadoop-2.9.0/logs
[root@sht-sgmhadoopdn-01 local]# tar -zcf hadoop-2.9.0.master.tar.gz /usr/local/hadoop-2.9.0
[root@sht-sgmhadoopdn-01 local]# scp hadoop-2.9.0.master.tar.gz sht-sgmhadoopdn-02:/usr/local/
在 Slave节点上执行
[root@sht-sgmhadoopdn-02 local]# tar -zxf hadoop-2.9.0.master.tar.gz
启动hadoop集群
在 master节点上执行：
#第一次启动需要格式化HDFS,以后再启动不需要
[root@sht-sgmhadoopdn-01 hadoop-2.9.0]# hdfs namenode -format
[root@sht-sgmhadoopdn-01 hadoop-2.9.0]# start-dfs.sh
[root@sht-sgmhadoopdn-01 hadoop-2.9.0]# start-yarn.sh
[root@sht-sgmhadoopdn-01 hadoop-2.9.0]# mr-jobhistory-daemon.sh start historyserver
[root@sht-sgmhadoopdn-01 hadoop-2.9.0]# jps
20289 JobHistoryServer
19730 ResourceManager
18934 NameNode
19163 SecondaryNameNode
20366 Jps
在 Slave节点上执行：
[root@sht-sgmhadoopdn-02 hadoop]# jps
32147 DataNode
535 Jps
32559 NodeManager
在 master节点上执行：
[root@sht-sgmhadoopdn-01 hadoop]# hdfs dfsadmin -report
Configured Capacity: 75831140352 (70.62 GB)
Present Capacity: 21246287872 (19.79 GB)
DFS Remaining: 21246263296 (19.79 GB)
DFS Used: 24576 (24 KB)
DFS Used%: 0.00%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0
Pending deletion blocks: 0
-------------------------------------------------
Live datanodes (1): #存活的slave数量
Name: 172.16.101.59:50010 (sht-sgmhadoopdn-02)
Hostname: sht-sgmhadoopdn-02
Decommission Status : Normal
Configured Capacity: 75831140352 (70.62 GB)
DFS Used: 24576 (24 KB)
Non DFS Used: 50732867584 (47.25 GB)
DFS Remaining: 21246263296 (19.79 GB)
DFS Used%: 0.00%
DFS Remaining%: 28.02%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 1
Last contact: Wed Dec 27 11:08:46 CST 2017
Last Block Report: Wed Dec 27 11:02:01 CST 2017
Console管理平台
NameNodehttp://172.16.101.58:50070
执行分布式实例MapReduce Job
[root@sht-sgmhadoopdn-01 hadoop]# hdfs dfs -mkdir -p /user/root/input
[root@sht-sgmhadoopdn-01 hadoop]# hdfs dfs -put /usr/local/hadoop-2.9.0/etc/hadoop/*.xml input
[root@sht-sgmhadoopdn-01 hadoop]# hadoop jar /usr/local/hadoop-2.9.0/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.9.0.jar grep input output 'dfs[a-z.]+'
17/12/27 11:25:33 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
17/12/27 11:25:34 INFO client.RMProxy: Connecting to ResourceManager at /172.16.101.58:8032
17/12/27 11:25:36 INFO input.FileInputFormat: Total input files to process : 9
17/12/27 11:25:36 INFO mapreduce.JobSubmitter: number of splits:9
17/12/27 11:25:37 INFO Configuration.deprecation: yarn.resourcemanager.system-metrics-publisher.enabled is deprecated. Instead, use yarn.system-metrics-publisher.enabled
17/12/27 11:25:37 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1514343869308_0001
17/12/27 11:25:38 INFO impl.YarnClientImpl: Submitted application application_1514343869308_0001
17/12/27 11:25:38 INFO mapreduce.Job: The url to track the job:http://sht-sgmhadoopdn-01:8088/proxy/application_1514343869308_0001/
17/12/27 11:25:38 INFO mapreduce.Job: Running job: job_1514343869308_0001
17/12/27 11:25:51 INFO mapreduce.Job: Job job_1514343869308_0001 running in uber mode : false
17/12/27 11:25:51 INFO mapreduce.Job: map 0% reduce 0%
17/12/27 11:26:14 INFO mapreduce.Job: map 11% reduce 0%
17/12/27 11:26:15 INFO mapreduce.Job: map 67% reduce 0%
17/12/27 11:26:29 INFO mapreduce.Job: map 100% reduce 0%
17/12/27 11:26:32 INFO mapreduce.Job: map 100% reduce 100%
17/12/27 11:26:34 INFO mapreduce.Job: Job job_1514343869308_0001 completed successfully
17/12/27 11:26:34 INFO mapreduce.Job: Counters: 50
......
[root@sht-sgmhadoopdn-01 hadoop]# hdfs dfs -cat output/*
17/12/27 11:30:08 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
1 dfsadmin
1 dfs.replication
1 dfs.namenode.secondary.http
1 dfs.namenode.name.dir
1 dfs.datanode.data.dir
也可以通过浏览器访问console，查看详细的分析信息：
ResourceManager -http://172.16.101.58:8088
停止hadoop集群
在 master节点上执行：
[root@sht-sgmhadoopdn-01 hadoop]#stop-yarn.sh
[root@sht-sgmhadoopdn-01 hadoop]#stop-dfs.sh
[root@sht-sgmhadoopdn-01 hadoop]#mr-jobhistory-daemon.sh stop historyserver
参考链接：
http://www.powerxing.com/install-hadoop-cluster/
http://hadoop.apache.org/docs/r2.9.0/hadoop-project-dist/hadoop-common/ClusterSetup.html
