Hadoop入门--HDFS（单节点）配置和部署(一)

一 配置SSH 下载ssh服务端和客户端 sudo apt-get install openssh-server openssh-client 验证是否安装成功 ssh username@192.168.30.128按照提示输入username的密码，回车后显示以下，则成功。(此处不建议修改端口号，hadoop默认的是22,修改后启动hadoop会

一 配置SSH

下载ssh服务端和客户端 sudo apt-get install openssh-server openssh-client 验证是否安装成功 ssh username@192.168.30.128按照提示输入username的密码，回车后显示以下，则成功。(此处不建议修改端口号，hadoop默认的是22,修改后启动hadoop会报异常，除非在hadoop的配置文件中也修改ssh端口号)Welcome to Ubuntu 13.04 (GNU/Linux 3.8.0-34-generic i686)

* Documentation: https://help.ubuntu.com/

New release '13.10' available.
Run 'do-release-upgrade' to upgrade to it.

Last login: Sun Dec 8 10:27:38 2013 from ubuntu.local 公钥-私钥登录配置（无密） ssh-keygen -t rsa -P ""（其中会出现输入提示，回车即可，之后home/username/.ssh/ 下生成id_rsa ，id_rsa.pub， known_hosts三个文件。
/home/username/ 下生成 authorized_keys 文件）将id_rsa.pub追加到authorized_keys授权文件中 cat .ssh/id_rsa >> authorized_keys （切换到/home/username/下）公钥-私钥登录配置（有密） ssh-keygen -t rsa （在出现 Enter passphrase (empty for no passphrase):
时，输入设置的密码。其它同上，此处未测试过）

二 安装JDK（采用OpenJDK，为啥不用JDK...百度or谷歌）

下载jdk sudo apt-get install openjdk-7-jdk（目前最新的是openjdk-7）配置环境变量 sudo vim ～/.bashrc （在文件末尾添加） export JAVA_HOME=/usr/lib/jvm/java-1.6.0-openjdk-i386
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH（修改环境变量生效）source ~/.bashrc
测试jdk是否安装成功 java -version（出现以下信息则成功）java version "1.7.0_25"
OpenJDK Runtime Environment (IcedTea 2.3.10) (7u25-2.3.10-1ubuntu0.13.04.2)
OpenJDK Client VM (build 23.7-b01, mixed mode, sharing)

三 安装Hadoop和HDFS配置

下载hadoop tar -zxvf hadoop-1.2.1.tar.gz（解压到 hadoop-1.2.1目录下）mv hadoop-1.2.1 hadoop（hadoop-1.2.1目录改名为hadoop）cp hadoop /usr/local（复制hadoop到 /usr/local 目录下）
配置hdfs文件（hadoop<code class="bash plain">/conf/core-site<code class="bash plain">.xml，<code class="bash plain">hadoop<code class="bash plain">/conf/hdfs-site<code class="bash plain">.xml，<code class="bash plain">hadoop<code class="bash plain">/conf/mapred-site<code class="bash plain">.xml） sudo vim /usr/local/<code class="bash plain">hadoop<code class="bash plain">/conf/core-site<code class="bash plain">.xml（修改为以下内容） <?xml version="1.0"?><br> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?><br> <br> <!-- Put site-specific property overrides in this file. --><br> <br> <configuration><br> <property><br> <name>fs.default.name</name><br> <value>hdfs://192.168.30.128:9000</value><br> </property><br> </configuration><br> sudo vim /usr/local/<code class="bash plain">hadoop<code class="bash plain">/conf/hdfs-site<code class="bash plain">.xml（修改为以下内容） <?xml version="1.0"?><br> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?><br> <br> <!-- Put site-specific property overrides in this file. --><br> <br> <configuration><br> <property><br> <name>hadoop.tmp.dir</name><br> <value>/home/username/hadoop_tmp</value><!--需要创建此目录--><br> <description>A base for other temporary directories.</description><br> </property><br> <property><br> <name>dfs.name.dir</name><br> <value>/tmp/hadoop/dfs/datalog1,/tmp/hadoop/dfs/datalog2</value><br> </property><br> <property><br> <name>dfs.data.dir</name><br> <value>/tmp/hadoop/dfs/data1,/tmp/hadoop/dfs/data2</value><br> </property><br> <property><br> <name>dfs.replication</name><br> <value>2</value><br> </property><br> sudo vim /usr/local/<code class="bash plain">hadoop<code class="bash plain">/conf/mapred-site<code class="bash plain">.xml（修改为以下内容） <?xml version="1.0"?><br> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?><br> <br> <!-- Put site-specific property overrides in this file. --><br> <br> <configuration><br> <property><br> <name>mapred.job.tracker</name><br> <value>192.168.30.128:9001</value><br> </property><br> </configuration>

<code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain">四 运行wordcount

<code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain"><code class="bash plain">在hdfs中创建一个统计目录，输出目录不用创建，否则运行wordcount的时候报错。 ./hadoop fs -mkdir /input./hadoop fs -put myword.txt /input./hadoop jar /usr/local/hadoop/hadoop-examples-1.2.1.jar wordcount /input /output./hadoop fs -cat <strong>/output/part-r-00000</strong>