01_Hadoop

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学习目标：

第一天接触具体的大数据框架，总目标是让学习者建立起大数据和分布式的宏观概念
1、理解hadoop是什么，用于做什么，大体上怎么用
2、理解hive是什么，用于做什么，大体上怎么用
3、通过一个案例的演示说明，理解数据挖掘系统的基本流程和结构

HADOOP背景介绍

什么是HADOOP

HADOOP是apache旗下的一套开源软件平台
HADOOP提供的功能：利用服务器集群，根据用户的自定义业务逻辑，对海量数据进行分布式处理
HADOOP的核心组件有
- HDFS（分布式文件系统）
- YARN（运算资源调度系统）
- MAPREDUCE（分布式运算编程框架）
广义上来说，HADOOP通常是指一个更广泛的概念——HADOOP生态圈

HADOOP产生背景

HADOOP最早起源于Nutch。Nutch的设计目标是构建一个大型的全网搜索引擎，包括网页抓取、索引、查询等功能，但随着抓取网页数量的增加，遇到了严重的可扩展性问题——如何解决数十亿网页的存储和索引问题。
2003年、2004年谷歌发表的两篇论文为该问题提供了可行的解决方案。
——分布式文件系统（GFS），可用于处理海量网页的存储
——分布式计算框架MAPREDUCE，可用于处理海量网页的索引计算问题。
Nutch的开发人员完成了相应的开源实现HDFS和MAPREDUCE，并从Nutch中剥离成为独立项目HADOOP，到2008年1月，HADOOP成为Apache顶级项目，迎来了它的快速发展期。

HADOOP在大数据、云计算中的位置和关系

云计算是分布式计算、并行计算、网格计算、多核计算、网络存储、虚拟化、负载均衡等传统计算机技术和互联网技术融合发展的产物。借助IaaS(基础设施即服务)、PaaS(平台即服务)、SaaS（软件即服务）等业务模式，把强大的计算能力提供给终端用户。
现阶段，云计算的两大底层支撑技术为“虚拟化”和“大数据技术”
而HADOOP则是云计算的PaaS层的解决方案之一，并不等同于PaaS，更不等同于云计算本身。

国内外HADOOP应用案例介绍

HADOOP应用于数据服务基础平台建设

HADOOP用于用户画像

HADOOP用于网站点击流日志数据挖掘

Hadoop集群搭建

Hadoop编译

1，环境：虚拟机 VirtualBox，
2，操作系统： 64 位 CentOS 6.4

下载编译需要的软件包

apache-ant-1.9.4-bin.tar.gz
findbugs-3.0.0.tar.gz
protobuf-2.5.0.tar.gz
apache-maven-3.0.5-bin.tar.gz

下载 hadoop2.4.0 的源码包
hadoop-2.4.0-src.tar.gz
压解源码包

[grid@hadoopMaster01 ~]$ tar -zxvf hadoop-2.4.0-src.tar.gz

安装编译所需软件

安装 MAVEN
- 压解 apache-maven-3.0.5-bin.tar.gz 到/opt/目录
  [root@hadoopMaster01 grid]# tar -zxvf apache-maven-3.0.5-bin.tar.gz -C /opt/
- 修改/etc/profile 配置，增加 MAVEN 环境配置M2_HOME PATH
- 保存后使用 source /etc/profile 使修改配置即时生效
  [root@hadoopMaster01 apache-maven-3.0.5]# source /etc/profile
- 使用 mvn -v 命令进行验证，如图所示表示安装配置成功
安装 ANT
- 压解 apache-ant-1.9.4-bin.tar.gz 到/opt/目录
  [root@hadoopMaster01 grid]# tar -zxvf apache-ant-1.9.4-bin.tar.gz -C /opt/
- 修改/etc/profile 配置，增加 ANT 环境配置 ANT_HOME PATH
- 保存后使用 source /etc/profile 使修改配置即时生效
  [root@hadoopMaster01 apache-ant-1.9.4]# source /etc/profile
- 使用 ant-version 命令进行验证，如图所示表示安装配置成功
安装 FINDBUGS
- 压解 findbugs-3.0.0.tar.gz 到/opt/目录
  [root@hadoopMaster01 grid]# tar -zxvf findbugs-3.0.0.tar.gz -C /opt/
- 修改/etc/profile 配置，增加 FINDBUGS 环境配置
- 保存后使用 source /etc/profile 使修改配置即时生效
  [root@hadoopMaster01 apache-ant-1.9.4]# source /etc/profile
- 使用 findbugs-version 命令进行验证，如图所示表示安装配置成功
安装 PROTOBUF
- 编译 Hadoop 2.4.0，需要 protobuf 的编译器protoc，一定要是 protobuf 2.5.0 以上
- 直接压解 protobuf-2.5.0.tar.gz
  [root@hadoopMaster01 grid]# tar -zxvf protobuf-2.5.0.tar.gz
- 安装 protobuf，依次执行如下命令

[root@hadoopMaster01 grid]# cd protobuf-2.5.0
[root@hadoopMaster01 protobuf-2.5.0]# ls
aclocal.m4 config.guess configure COPYING.txt examples
install-sh ltmain.sh Makefile.in protobuf.pc.in src
autogen.sh config.h.in configure.ac depcomp generate_descriptor_proto.sh
INSTALL.txt m4 missing python vsprojects
CHANGES.txt config.sub CONTRIBUTORS.txt editors gtest
java Makefile.am protobuf-lite.pc.in README.txt
[root@hadoopMaster01 protobuf-2.5.0]# ./configure
[root@hadoopMaster01 protobuf-2.5.0]# make
[root@hadoopMaster01 protobuf-2.5.0]# make check
[root@hadoopMaster01 protobuf-2.5.0]# make install

使用 protoc --version 命令进行验证，如图所示表示安装配置成功

安装依赖包
- 安装 cmake,openssl-devel,ncurses-devel 依赖包(root 用户且能够连上互联网)
  [root@hadoopMaster01 ~]# yum install cmake
  如下图表示安装成功
  [root@hadoopMaster01 ~]# yum install openssl-devel
  如下图表示安装成功
  [root@hadoopMaster01 ~]# yum install ncurses-devel
  如下图表示依赖包系统中已经安装并且为最新版本
编译 64 位本地库
- 进入已解压的 hadoop 源码目录
  [grid@hadoopMaster01 ~]$ cd hadoop-2.4.0-src
  [grid@hadoopMaster01 hadoop-2.4.0-src]$ pwd
  /home/grid/hadoop-2.4.0-src
- 执行 mvn clean install -DskipTests 命令，等待完成(会自动联网下载很多东西，会执行相当长的时间)
  [grid@hadoopMaster01 hadoop-2.4.0-src]$ mvn clean install -DskipTests
- 执行 mvn package -Pdist,native -DskipTests -Dtar 命令，开始编译，等待完成
  grid@hadoopMaster01 hadoop-2.4.0-src]$ mvn package -Pdist,native -DskipTests -Dtar
  出现如下信息

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Apache Hadoop Main ................................ SUCCESS[6.304s]
[INFO] Apache Hadoop Project POM ......................... SUCCESS [26.555s]
[INFO] Apache Hadoop Annotations ......................... SUCCESS[2.757s]
[INFO] Apache Hadoop Assemblies .......................... SUCCESS [0.216s]
[INFO] Apache Hadoop Project Dist POM .................... SUCCESS [19.592s]
[INFO] Apache Hadoop Maven Plugins ....................... SUCCESS [2.715s]
[INFO] Apache Hadoop MiniKDC ............................. SUCCESS [2.360s]
[INFO] Apache Hadoop Auth ................................ SUCCESS [2.950s]
[INFO] Apache Hadoop Auth Examples ....................... SUCCESS[2.119s]
[INFO] Apache Hadoop Common .............................. SUCCESS [1:22.302s]
[INFO] Apache Hadoop NFS ................................. SUCCESS [5.095s]
[INFO] Apache Hadoop Common Project...................... SUCCESS [0.026s]
[INFO] Apache Hadoop HDFS ................................ SUCCESS [2:06.178s]
[INFO] Apache Hadoop HttpFS .............................. SUCCESS [1:09.142s]
[INFO] Apache Hadoop HDFS BookKeeper Journal ............. SUCCESS [14.457s]
[INFO] Apache Hadoop HDFS-NFS ............................SUCCESS [2.859s]
[INFO] Apache Hadoop HDFS Project ........................ SUCCESS [0.030s]
[INFO] hadoop-yarn ....................................... SUCCESS [0.029s]
[INFO] hadoop-yarn-api ................................... SUCCESS [59.010s]
[INFO] hadoop-yarn-common ................................ SUCCESS [20.743s]
[INFO] hadoop-yarn-server ................................ SUCCESS[0.026s]
[INFO] hadoop-yarn-server-common ......................... SUCCESS [7.344s]
[INFO] hadoop-yarn-server-nodemanager .................... SUCCESS [11.726s]
[INFO] hadoop-yarn-server-web-proxy ...................... SUCCESS [2.508s]
[INFO] hadoop-yarn-server-applicationhistoryservice ...... SUCCESS [4.041s]
[INFO] hadoop-yarn-server-resourcemanager ................ SUCCESS [10.370s]
[INFO] hadoop-yarn-server-tests .......................... SUCCESS [0.374s]
[INFO] hadoop-yarn-client ................................ SUCCESS [4.791s]
[INFO] hadoop-yarn-applications .......................... SUCCESS [0.025s]
[INFO] hadoop-yarn-applications-distributedshell ......... SUCCESS [2.242s]
[INFO] hadoop-yarn-applications-unmanaged-am-launcher .... SUCCESS [1.553s]
[INFO] hadoop-yarn-site .................................. SUCCESS [0.024s]
[INFO] hadoop-yarn-project ............................... SUCCESS [3.261s]
[INFO] hadoop-mapreduce-client ........................... SUCCESS [0.082s]
[INFO] hadoop-mapreduce-client-core ...................... SUCCESS [18.549s]
[INFO] hadoop-mapreduce-client-common .................... SUCCESS [13.772s]
[INFO] hadoop-mapreduce-client-shuffle ................... SUCCESS [2.441s]
[INFO] hadoop-mapreduce-client-app ....................... SUCCESS [6.866s]
[INFO] hadoop-mapreduce-client-hs ........................ SUCCESS [6.280s]
[INFO] hadoop-mapreduce-client-jobclient .................SUCCESS [3.510s]
[INFO] hadoop-mapreduce-client-hs-plugins ................ SUCCESS [1.725s]
[INFO] Apache Hadoop MapReduce Examples .................. SUCCESS [4.641s]
[INFO] hadoop-mapreduce .................................. SUCCESS[3.002s]
[INFO] Apache Hadoop MapReduce Streaming ................. SUCCESS [3.497s]
[INFO] Apache Hadoop Distributed Copy .................... SUCCESS [5.847s]
[INFO] Apache Hadoop Archives ............................ SUCCESS [1.791s]
[INFO] Apache Hadoop Rumen ............................... SUCCESS [4.693s]
[INFO] Apache Hadoop Gridmix ............................. SUCCESS [3.235s]
[INFO] Apache Hadoop Data Join........................... SUCCESS [2.349s]
[INFO] Apache Hadoop Extras .............................. SUCCESS [2.488s]
[INFO] Apache Hadoop Pipes ............................... SUCCESS [5.863s]
[INFO] Apache Hadoop OpenStack support ................... SUCCESS [3.776s]
[INFO] Apache Hadoop Client .............................. SUCCESS [5.235s]
[INFO] Apache Hadoop Mini-Cluster ........................ SUCCESS [0.070s]
[INFO] Apache Hadoop Scheduler Load Simulator ............ SUCCESS [3.935s]
[INFO] Apache Hadoop Tools Dist .......................... SUCCESS [4.392s]
[INFO] Apache Hadoop Tools ............................... SUCCESS [0.022s]
[INFO] Apache Hadoop Distribution ........................ SUCCESS [21.274s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 10:25.147s
[INFO] Finished at: Mon Jul 28 16:09:56 CST 2014
[INFO] Final Memory: 75M/241M
[INFO] ------------------------------------------------------------------------

表示编译成功
进入/home/grid/hadoop-2.4.0-src/hadoop-dist/target/hadoop-2.4.0/lib/native 检查，使用 file *命令，如下图已经成功将编译 64 本地库
将 64 位的 native 文件夹替换原 32 位的文件夹即可

HAadoop安装配置、启动

本案例使用四台主机mini1、mini2、mini3、mini4搭建Hadoop集群，其中mini1为namenode，其他三台为datanode。

前提条件

确保四台主机都已经配置好java环境
确保四台主机都能使用scp命令(安装了openssh_client)
mini1能通过SSH免密登录到其他三台主机(教程后面有配置的步骤)
四台主机都设置了hostname，使用hostname -f命令能看到mini1，mini2...，要使用hostname -f命令看到正确的值，必须/etc/sysconfig/network和/etc/hosts都正确配置，然后重启电脑hostname生效
关闭四台机的防火墙，这个不是一定要这样的，可以配置端口开放

[hadoop@mini1 ~]$ su
Password: 
[root@mini1 hadoop]# service iptables stop
iptables: Setting chains to policy ACCEPT: filter          [  OK  ]
iptables: Flushing firewall rules:                         [  OK  ]
iptables: Unloading modules:                               [  OK  ]
[root@mini1 hadoop]# chkconfig iptables off
[root@mini1 hadoop]#

步骤

给四台主机添加hadoop的用户，设置密码为hadoop

useradd hadoop
passwd hadoop

给hadoop用户添加root权限
vi /etc/sudoers

## Allow root to run any commands anywhere
root    ALL=(ALL)       ALL
hadoop  ALL=(ALL)       ALL

拷贝到mini2上

[root@mini1 ~]# scp /etc/sudoers mini2:/etc/
Warning: Permanently added the RSA host key for IP address '192.168.230.202' to the list of known hosts.
root@mini2's password: 
sudoers

scp /etc/sudoers mini2:/etc/
scp /etc/sudoers mini3:/etc/
scp /etc/sudoers mini4:/etc/

然后使用hadoop用户重新连接到这四台主机
上传hadoop包
- 本案例使用已经编译好的cenos-6.5-hadoop-2.6.4.tar.gz包
- 上传到mini1：put D:\linux_file\cenos-6.5-hadoop-2.6.4.tar.gz
解压

[hadoop@mini1 ~]$ pwd
/home/hadoop
[hadoop@mini1 ~]$ mkdir apps
[hadoop@mini1 ~]$ tar zxvf cenos-6.5-hadoop-2.6.4.tar.gz -C apps/

[hadoop@mini1 ~]$ cd apps/
[hadoop@mini1 apps]$ cd hadoop-2.6.4/
[hadoop@mini1 hadoop-2.6.4]$ ll
total 52
drwxrwxr-x. 2 hadoop hadoop  4096 Mar  7  2016 bin
drwxrwxr-x. 3 hadoop hadoop  4096 Mar  7  2016 etc
drwxrwxr-x. 2 hadoop hadoop  4096 Mar  7  2016 include
drwxrwxr-x. 3 hadoop hadoop  4096 Mar  7  2016 lib
drwxrwxr-x. 2 hadoop hadoop  4096 Mar  7  2016 libexec
-rw-r--r--. 1 hadoop hadoop 15429 Mar  7  2016 LICENSE.txt
-rw-r--r--. 1 hadoop hadoop   101 Mar  7  2016 NOTICE.txt
-rw-r--r--. 1 hadoop hadoop  1366 Mar  7  2016 README.txt
drwxrwxr-x. 2 hadoop hadoop  4096 Mar  7  2016 sbin
drwxrwxr-x. 4 hadoop hadoop  4096 Mar  7  2016 share
[hadoop@mini1 hadoop-2.6.4]$ cd etc/hadoop/
[hadoop@mini1 hadoop]$ ll
total 152
-rw-r--r--. 1 hadoop hadoop  4436 Mar  7  2016 capacity-scheduler.xml
-rw-r--r--. 1 hadoop hadoop  1335 Mar  7  2016 configuration.xsl
-rw-r--r--. 1 hadoop hadoop   318 Mar  7  2016 container-executor.cfg
-rw-r--r--. 1 hadoop hadoop   774 Mar  7  2016 core-site.xml
-rw-r--r--. 1 hadoop hadoop  3670 Mar  7  2016 hadoop-env.cmd
-rw-r--r--. 1 hadoop hadoop  4224 Mar  7  2016 hadoop-env.sh
-rw-r--r--. 1 hadoop hadoop  2598 Mar  7  2016 hadoop-metrics2.properties
-rw-r--r--. 1 hadoop hadoop  2490 Mar  7  2016 hadoop-metrics.properties
-rw-r--r--. 1 hadoop hadoop  9683 Mar  7  2016 hadoop-policy.xml
-rw-r--r--. 1 hadoop hadoop   775 Mar  7  2016 hdfs-site.xml
-rw-r--r--. 1 hadoop hadoop  1449 Mar  7  2016 httpfs-env.sh
-rw-r--r--. 1 hadoop hadoop  1657 Mar  7  2016 httpfs-log4j.properties
-rw-r--r--. 1 hadoop hadoop    21 Mar  7  2016 httpfs-signature.secret
-rw-r--r--. 1 hadoop hadoop   620 Mar  7  2016 httpfs-site.xml
-rw-r--r--. 1 hadoop hadoop  3523 Mar  7  2016 kms-acls.xml
-rw-r--r--. 1 hadoop hadoop  1325 Mar  7  2016 kms-env.sh
-rw-r--r--. 1 hadoop hadoop  1631 Mar  7  2016 kms-log4j.properties
-rw-r--r--. 1 hadoop hadoop  5511 Mar  7  2016 kms-site.xml
-rw-r--r--. 1 hadoop hadoop 11291 Mar  7  2016 log4j.properties
-rw-r--r--. 1 hadoop hadoop   938 Mar  7  2016 mapred-env.cmd
-rw-r--r--. 1 hadoop hadoop  1383 Mar  7  2016 mapred-env.sh
-rw-r--r--. 1 hadoop hadoop  4113 Mar  7  2016 mapred-queues.xml.template
-rw-r--r--. 1 hadoop hadoop   758 Mar  7  2016 mapred-site.xml.template
-rw-r--r--. 1 hadoop hadoop    10 Mar  7  2016 slaves
-rw-r--r--. 1 hadoop hadoop  2316 Mar  7  2016 ssl-client.xml.example
-rw-r--r--. 1 hadoop hadoop  2268 Mar  7  2016 ssl-server.xml.example
-rw-r--r--. 1 hadoop hadoop  2237 Mar  7  2016 yarn-env.cmd
-rw-r--r--. 1 hadoop hadoop  4567 Mar  7  2016 yarn-env.sh
-rw-r--r--. 1 hadoop hadoop   690 Mar  7  2016 yarn-site.xml

配置hadoop-env.sh

[hadoop@mini1 hadoop]$ echo $JAVA_HOME
/usr/local/jdk1.7.0_45
[hadoop@mini1 hadoop]$ vi hadoop-env.sh

配置下面这一行如下：

# The java implementation to use.
export JAVA_HOME=/usr/local/jdk1.7.0_45

配置core-site.xml，如下

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://mini1:9000</value>
</property>

<property>
<name>hadoop.tmp.dir</name>
<value>/home/hadoop/hdpdata</value>
</property>
</configuration>

配置hdfs-site.xml，如下：

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
</configuration>

配置mapred-site.xml

[hadoop@mini1 hadoop]$ mv mapred-site.xml.template mapred-site.xml
[hadoop@mini1 hadoop]$ vi mapred-site.xml

配置如下：

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>

配置yarn-site.xml，如下：

<?xml version="1.0"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->
<configuration>

<!-- Site specific YARN configuration properties -->
<property>
<name>yarn.resourcemanager.hostname</name>
<value>mini1</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>

</configuration>

将配置好的hadoop拷贝到其他三台主机

[hadoop@mini1 hadoop-2.6.4]$ cd ~
[hadoop@mini1 ~]$ scp -r apps/ mini2:/home/hadoop
[hadoop@mini1 ~]$ scp -r apps/ mini3:/home/hadoop
[hadoop@mini1 ~]$ scp -r apps/ mini4:/home/hadoop

将hadoop配置到环境变量最后
vi /etc/profile

export JAVA_HOME=/usr/local/jdk1.7.0_45
export HADOOP_HOME=/home/hadoop/apps/hadoop-2.6.4
export PATH=$PATH:$JAVA_HOME/bin:$HADOOP_HOME/bin:$HADOOP_HOME/sbin

将配置好的环境变量拷贝到其他三台机器

[hadoop@mini1 ~]$ sudo scp /etc/profile mini2:/etc/
[hadoop@mini1 ~]$ sudo scp /etc/profile mini3:/etc/
[hadoop@mini1 ~]$ sudo scp /etc/profile mini4:/etc/

格式化mini1上的namenode的HDFS

[hadoop@mini1 ~]$ source /etc/profile
[hadoop@mini1 ~]$ hadoop namenode -format

启动和关闭

启动mini1上的namenode

[hadoop@mini1 ~]$ hadoop-daemon.sh start namenode
starting namenode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-namenode-mini1.out
[hadoop@mini1 ~]$

启动之后查看网页端的管理页面：
如果本机一配置好hosts，可以直接在浏览器输入：http://mini1:50070，
如果没有配置hosts,在浏览器输入：http://mini1的ip:50070

启动mini2上的datanode

[hadoop@mini2 ~]$ source /etc/profile
[hadoop@mini2 ~]$ hadoop-daemon.sh start datanode
starting datanode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-datanode-mini2.out
[hadoop@mini2 ~]$

然后刷新mini1的web管理端

可以看到添加了一个节点

启动mini3上的datanode

[hadoop@mini3 ~]$ source /etc/profile
[hadoop@mini3 ~]$ hadoop-daemon.sh start datanode
starting datanode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-datanode-mini3.out
[hadoop@mini3 ~]$

然后刷新mini1的web管理端

可以看到又添加了一个节点

同理启动mini4的datanode
关闭mini2、3、4的datanode

[hadoop@mini3 ~]$ hadoop-daemon.sh stop datanode
stopping datanode

关闭mini1的namenode

[hadoop@mini1 ~]$ hadoop-daemon.sh stop namenode
stopping namenode
[hadoop@mini1 ~]$

集群启动

在/home/hadoop/apps/hadoop-2.6.4/sbin下，有启动集群的脚本

[hadoop@mini1 sbin]$ ll
total 120
-rwxr-xr-x. 1 hadoop hadoop 2752 Mar  7  2016 distribute-exclude.sh
-rwxr-xr-x. 1 hadoop hadoop 6452 Mar  7  2016 hadoop-daemon.sh
-rwxr-xr-x. 1 hadoop hadoop 1360 Mar  7  2016 hadoop-daemons.sh
-rwxr-xr-x. 1 hadoop hadoop 1640 Mar  7  2016 hdfs-config.cmd
-rwxr-xr-x. 1 hadoop hadoop 1427 Mar  7  2016 hdfs-config.sh
-rwxr-xr-x. 1 hadoop hadoop 2291 Mar  7  2016 httpfs.sh
-rwxr-xr-x. 1 hadoop hadoop 2059 Mar  7  2016 kms.sh
-rwxr-xr-x. 1 hadoop hadoop 4080 Mar  7  2016 mr-jobhistory-daemon.sh
-rwxr-xr-x. 1 hadoop hadoop 1648 Mar  7  2016 refresh-namenodes.sh
-rwxr-xr-x. 1 hadoop hadoop 2145 Mar  7  2016 slaves.sh
-rwxr-xr-x. 1 hadoop hadoop 1779 Mar  7  2016 start-all.cmd
-rwxr-xr-x. 1 hadoop hadoop 1471 Mar  7  2016 start-all.sh
-rwxr-xr-x. 1 hadoop hadoop 1128 Mar  7  2016 start-balancer.sh
-rwxr-xr-x. 1 hadoop hadoop 1401 Mar  7  2016 start-dfs.cmd
-rwxr-xr-x. 1 hadoop hadoop 3705 Mar  7  2016 start-dfs.sh
-rwxr-xr-x. 1 hadoop hadoop 1357 Mar  7  2016 start-secure-dns.sh
-rwxr-xr-x. 1 hadoop hadoop 1571 Mar  7  2016 start-yarn.cmd
-rwxr-xr-x. 1 hadoop hadoop 1347 Mar  7  2016 start-yarn.sh
-rwxr-xr-x. 1 hadoop hadoop 1770 Mar  7  2016 stop-all.cmd
-rwxr-xr-x. 1 hadoop hadoop 1462 Mar  7  2016 stop-all.sh
-rwxr-xr-x. 1 hadoop hadoop 1179 Mar  7  2016 stop-balancer.sh
-rwxr-xr-x. 1 hadoop hadoop 1455 Mar  7  2016 stop-dfs.cmd
-rwxr-xr-x. 1 hadoop hadoop 3206 Mar  7  2016 stop-dfs.sh
-rwxr-xr-x. 1 hadoop hadoop 1340 Mar  7  2016 stop-secure-dns.sh
-rwxr-xr-x. 1 hadoop hadoop 1642 Mar  7  2016 stop-yarn.cmd
-rwxr-xr-x. 1 hadoop hadoop 1340 Mar  7  2016 stop-yarn.sh
-rwxr-xr-x. 1 hadoop hadoop 4295 Mar  7  2016 yarn-daemon.sh
-rwxr-xr-x. 1 hadoop hadoop 1353 Mar  7  2016 yarn-daemons.sh

在/home/hadoop/apps/hadoop-2.6.4/etc/hadoop下的slaves文件可以配置集群中的其他主机

配置集群中的其他主机

[hadoop@mini1 hadoop]$ vi slaves，配置如下：

mini2
mini3
mini4

配置mini1对其他三台主机的免密登录
因为一般都在mini1的namenode上启动集群
- 生成秘钥

[hadoop@mini1 hadoop]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/hadoop/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/hadoop/.ssh/id_rsa.
Your public key has been saved in /home/hadoop/.ssh/id_rsa.pub.
The key fingerprint is:
22:b9:12:a5:05:f9:e2:5c:97:9f:d6:7a:52:27:6a:41 hadoop@mini1
The key's randomart image is:
+--[ RSA 2048]----+
|  ..             |
|  ..             |
|   .o  .         |
|  .+o.o E        |
| oooo..oSo       |
|  o. o .= + .    |
|  . .  . = o     |
|   .    = .      |
|       . o       |
+-----------------+
[hadoop@mini1 hadoop]$

配置到其他主机(包括自己)

[hadoop@mini1 hadoop]$ ssh-copy-id mini1
The authenticity of host 'mini1 (192.168.230.201)' can't be established.
RSA key fingerprint is 27:7a:bd:db:5c:79:ec:69:00:90:a5:02:66:48:ca:73.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'mini1,192.168.230.201' (RSA) to the list of known hosts.
hadoop@mini1's password: 
Now try logging into the machine, with "ssh 'mini1'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

[hadoop@mini1 hadoop]$ ssh-copy-id mini2
hadoop@mini2's password: 
Now try logging into the machine, with "ssh 'mini2'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

[hadoop@mini1 hadoop]$ ssh-copy-id mini3
hadoop@mini3's password: 
Now try logging into the machine, with "ssh 'mini3'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

[hadoop@mini1 hadoop]$ ssh-copy-id mini4
hadoop@mini4's password: 
Now try logging into the machine, with "ssh 'mini4'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

[hadoop@mini1 hadoop]$

启动HDFS集群

/home/hadoop/apps/hadoop-2.6.4/sbin
[hadoop@mini1 sbin]$ start-dfs.sh 
Starting namenodes on [mini1]
mini1: starting namenode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-namenode-mini1.out
mini3: starting datanode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-datanode-mini3.out
mini2: starting datanode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-datanode-mini2.out
mini4: starting datanode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-datanode-mini4.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /home/hadoop/apps/hadoop-2.6.4/logs/hadoop-hadoop-secondarynamenode-mini1.out
[hadoop@mini1 sbin]$

关闭HDFS集群