Hadoop2.x介绍与源代码编译

1、Hadoop 项目的四大模块

Hadoop Common: The common utilities that support the other Hadoop modules.
Hadoop Distributed File System (HDFS™): A distributed file system that provides high-throughput access to application data.
Hadoop YARN: A framework for job scheduling and cluster resource management.
Hadoop MapReduce: A YARN-based system for parallel processing of large data sets.

2、YARN：”云的操作系统”-- Hortonworks （Hadoop 商业版本号的）

给部署在YARN上的应用，分配资源
管理资源
JOB/APPLICATION 调度

3、技能

云计算，Hadoop 2.x
服务总线，SOA/OSB，Dubble
全文检索，Lucunce、Solr、Nutch

4、编译Hadoop 2.x 源代码
4.1、环境：

1）Linux 64 位操作系统。CentOS 6.4 版本号。VMWare 搭建的虚拟机

2）虚拟机能够联网

4.2、官方编译说明：

解压命令：tar -zxvf hadoop-2.2.0-src.tar.gz

之后进入到解压目录下，能够查看BUILDING.txt文件。 more BUILDING.txt 。向下翻页是空格键，当中内容例如以下

Requirements:

* Unix System

* JDK 1.6+

* Maven 3.0 or later

* Findbugs 1.3.9 (if running findbugs)

* ProtocolBuffer 2.5.0

* CMake 2.6 or newer (if compiling native code)

* Internet connection for first build (to fetch all Maven and Hadoop dependencies)

----------------------------------------------------------------------------------

Maven main modules:

hadoop (Main Hadoop project)

- hadoop-project (Parent POM for all Hadoop Maven modules. )

(All plugins & dependencies versions are defined here.)

- hadoop-project-dist (Parent POM for modules that generate distributions.)

- hadoop-annotations (Generates the Hadoop doclet used to generated the Java

docs)

- hadoop-assemblies (Maven assemblies used by the different modules)

- hadoop-common-project (Hadoop Common)

- hadoop-hdfs-project (Hadoop HDFS)

- hadoop-mapreduce-project (Hadoop MapReduce)

- hadoop-tools (Hadoop tools like Streaming, Distcp, etc.)

- hadoop-dist (Hadoop distribution assembler)

----------------------------------------------------------------------------------

在编译完毕之后，能够查看Hadoop的版本号信息

libhadoop.so.1.0.0: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped

[root@centos native]# pwd

/opt/hadoop-2.2.0-src/hadoop-dist/target/hadoop-2.2.0/lib/native

[root@centos native]#

4.3、编译前准备之安装依赖包



安装linux系统包

yum install autoconf automake libtool cmake
yum install ncurses-devel
yum install openssl-devel
yum install lzo-devel zlib-devel gcc gcc-c++

安装Maven

下载：apache-maven-3.0.5-bin.tar.gz
解压：tar -zxvf apache-maven-3.0.5-bin.tar.gz
环境变量设置，打开/etc/profile文件，加入

export MAVEN_HOME=/opt/apache-maven-3.0.5
export PATH=$PATH:$MAVEN_HOME/bin

运行命令使之生效：source /etc/profile或者./etc/profile
验证：mvn -v

安装protobuf

解压：tar -zxvf protobuf-2.5.0.tar.gz
进入安装文件夹，进行配置，运行命令。./configure
安装命令：make & make check & make install
验证：protoc --version

安装findbugs

解压：tar -zxvf findbugs.tar.gz
环境变量设置：

export export FINDBUGS_HOME=/opt/findbugs-3.0.0
export PATH=$PATH:$FINDBUGS_HOME/bin

验证命令：findbugs -version

假设出现信息：java lang unsupportedclassversionerror unsupported major minor version 51.0。那么是由于你採用的jdk为open jdk，直接将其卸载，安装Sun公司原装的JDK就可以，參考：
http://www.blogjava.net/Jay2009/archive/2009/04/23/267108.html
http://www.cnblogs.com/zhoulf/archive/2013/02/04/2891608.html

假设javac命令无法识别
[root@centos ~]# javac

Error: could not find libjava.so

Error: could not find Java 2 Runtime Environment.
可是当我这样执行的时候：/usr/lib/jvm/jdk1.7.0_71/bin/javac -version，一切正常，说明可能是旧版jre影响，那么删除open-jre，安装Sun公司Jre
下载了rpm包之后，rpm -ivh jre-7u71-linux-x64.rpm，安装完毕之后
[root@centos ~]# java -version

java version "1.7.0_71"

Java(TM) SE Runtime Environment (build 1.7.0_71-b14)

Java HotSpot(TM) 64-Bit Server VM (build 24.71-b01, mixed mode)

[root@centos ~]# javac -version

javac 1.7.0_71

[root@centos ~]#

注意

Hadoop是Java写的。他无法使用Linux预安装的OpenJDK,因此安装hadoop前须要先安装JDK（1.6以上）
另外Hadoop2.2.0存在一个bug
须要改动/opt/hadoop-2.2.0-src/hadoop-common-project/hadoop-auth/pom.xml中的内容（加入黑体部分）：

<dependency> <groupId>org.mortbay.jetty</groupId> <artifactId>jetty-util</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.mortbay.jetty</groupId> <artifactId>jetty</artifactId> <scope>test</scope> </dependency>

4.4、怎样编译

进入到Hadoop源代码文件夹下/opt/hadoop-2.2.0-src。执行红色字体[可选项]：

Building distributions:

Create binary distribution without native code and without documentation:

$ mvn package -Pdist -DskipTests -Dtar

Create binary distribution with native code and with documentation:

$ mvn package -Pdist,native,docs -DskipTests -Dtar

Create source distribution:

$ mvn package -Psrc -DskipTests

Create source and binary distributions with native code and documentation:

$ mvn
-e -X package -Pdist,native[,docs,src] -DskipTests -Dtar

Create a local staging version of the website (in /tmp/hadoop-site)

$ mvn clean site; mvn site:stage -DstagingDirectory=/tmp/hadoop-site

4.5、编译之前，可能须要配置MAVEN国内镜像配置

进入安装文件夹 /opt/modules/apache-maven-3.0.5/conf，编辑 settings.xml 文件

* 改动<mirrors>内容：

<mirror>

<id>nexus-osc</id>

<mirrorOf>*</mirrorOf>

<name>Nexus osc</name>

<url>http://maven.oschina.net/content/groups/public/</url>

</mirror>

* 改动<profiles>内容：

<profile>

<id>jdk-1.6</id>

<activation>

<jdk>1.6</jdk>

</activation>

<repositories>

<repository>

<id>nexus</id>

<name>local private nexus</name>

<url>http://maven.oschina.net/content/groups/public/</url>

<releases>

<enabled>true</enabled>

</releases>

<snapshots>

<enabled>false</enabled>

</snapshots>

</repository>

</repositories>

<pluginRepositories>

<pluginRepository>

<id>nexus</id>

<name>local private nexus</name>

<url>http://maven.oschina.net/content/groups/public/</url>

<releases>

<enabled>true</enabled>

</releases>

<snapshots>

<enabled>false</enabled>

</snapshots>

</pluginRepository>

</pluginRepositories>

</profile>

复制配置

将该配置文件拷贝到用户文件夹，使得每次对maven创建时，都採用该配置

* 查看用户文件夹【/home/hadoop】是否存在【.m2】文件夹，如没有。则创建

$ cd /home/hadoop

$ mkdir .m2

* 拷贝文件

$ cp /opt/modules/apache-maven-3.0.5/conf/settings.xml ~/.m2/

4.6、配置DNS

改动： vi /etc/resolv.conf

nameserver 8.8.8.8

nameserver 8.8.4.4

4.7、将Hadoop Project 导入到Eclipse

Importing projects to eclipse

When you import the project to eclipse, install hadoop-maven-plugins at first.

$ cd hadoop-maven-plugins

$ mvn install

Then, generate eclipse project files.

$ mvn eclipse:eclipse -DskipTests

At last, import to eclipse by specifying the root directory of the project via

[File] > [Import] > [Existing Projects into Workspace].

注意：

编译过程中假设出现不论什么有关jdk或者jre的问题：JAVA_HOME environment variable is not
set.

參看
http://www.cnblogs.com/RandyS/p/3909717.html
到 /etc/profile 最后，然后 . /etc/profile或者source /etc/profile使设置生效。

假设出现bash: javac: command not found
那么运行
yum install java-devel就可以，这是由于：http://stackoverflow.com/questions/5407703/javac-command-not-found

编译过程中碰到的其它问题：http://blog.csdn.net/xichenguan/article/details/17636905

出现错误：Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.6:run (site) on project hadoop-hdfs: An Ant BuildException has occured:
input file /opt/hadoop-2.2.0-src/hadoop-hdfs-project/hadoop-hdfs/target/findbugsXml.xml does not exist
解决的方法：
cd ~/hadoop-2.2.0-src/
mvn clean package -Pdist,native,docs -DskipTests -Dtar //编译中途出错修正后可从指定点開始继续编译，改动最后一个參数就可以。

如出现hadoop-hdfs/target/findbugsXml.xml
does not exist则从该命令删除docs參数再执行mvn package -Pdist,native -DskipTests -Dtar -rf :hadoop-pipes

build成功之后。进入到/opt/hadoop-2.2.0-src/hadoop-dist/target路径下查看hadoop-2.2.0.tar.gz就是编译完毕之后的tar包

出现错误：Could not find goal 'protoc' in plugin org.apache.hadoop:hadoop-maven-plugins:2.2.0 among available
解决的方法：在/etc/profile中增加例如以下内容，之后source /etc/profile
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/protobuf/lib

export PATH=$PATH:/usr/local/bin

通常建议安装到/usr/local文件夹下，运行configure时，指定--prefix=/usr/local/protobuf就可以，假设出现错误，那么make clean一下，之后再进行操作

我的/etc/profile文件内容：
export MAVEN_HOME=/opt/apache-maven-3.0.5
export PATH=$PATH:$MAVEN_HOME/bin
export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_71/
export JRE_HOME=/usr/lib/jvm/jdk1.7.0_71/jre
export ANT_HOME=/usr/lib/jvm/apache-ant/
export CLASSPATH=.:$JRE_HOME/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin:$ANT_HOME/bin
export FINDBUGS_HOME=/opt/findbugs-3.0.0
export PATH=$PATH:$FINDBUGS_HOME/bin:/opt/protoc/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/protoc/lib
第一次编译结果：





第二次编译结果：