如何为Hadoop2构建本机库

Question

我已经设置了一个在64位linux上运行Hadoop2.1beta的集群。但是，每次我运行hadoop命令工具时，都会弹出一条警告消息：

WARN util.NativeCodeLoader: Unable to load native-hadoop library for 
your platform...
using builtin-java classes where applicable

然后我发现它缺少64位linux的本地库。官方的Hadoop2.1tarball只在/lib/native文件夹中提供了32位linux的本地库。

我阅读了hadoop本机库的official document，该指南说：

Once you installed the prerequisite packages use the standard hadoop 
build.xml file and pass along the compile.native flag (set to true) to 
build the native hadoop library:

$ant -Dcompile.native=true <target>

我搜索hadoop文件夹，没有名为build.xml的文件。我没有足够的java编程和hadoop知识，所以我想知道如何编译64位linux系统的本地库？谢谢。

Answer 1

构建系统已更改为maven。您可以在此处找到构建说明：https://svn.apache.org/repos/asf/hadoop/common/trunk/BUILDING.txt

具体来说，您可以运行以下命令: mvn package -Pdist，native，docs -DskipTests -Dtar

(一旦你安装了protobuf 2.5.0)

Answer 2

下载并安装protobuf

wget http://protobuf.googlecode.com/files/protobuf-2.5.0.tar.gz /tmp
tar -xvf protobuf-2.5.0.tar.gz
cd /tmp/protobuf-2.5.0
sudo ./configure
sudo ./make install 
sudo ldconfig

安装cmake

sudo apt-get install cmake

使用maven构建本机库

mvn compile -Pnative

如果有任何错误，运行带有-e -X开关的maven，它将输出详细的调试信息。查看错误是什么，并进行适当的更改。

例如，我得到了以下错误：

[ERROR] Could not find goal 'protoc' in plugin org.apache.hadoop:hadoop-maven-plugins:3.0.0-SNAPSHOT among available goals -> [Help 1]

意味着你的protobuf版本不正确。

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-antrun-plugin:1.7:run (make) on project hadoop-common: An Ant BuildException has occured: Execute failed: java.io.IOException: Cannot run program "cmake" (in directory "/tmp/hadoop-2.5.0-src/hadoop-common-project/hadoop-common/target/native"): error=2, No such file or directory

未安装cmake。

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.8.1:jar (module-javadocs) on project hadoop-annotations: MavenReportException: Error while creating archive:
[ERROR] Exit code: 1 - /tmp/hadoop-2.5.0-src/hadoop-common-project/hadoop-annotations/src/main/java/org/apache/hadoop/classification/InterfaceStability.java:27: error: unexpected end tag: </ul>
[ERROR] * </ul>

不知道问题出在哪里。只需通过将-Dmaven.javadoc.skip=true标志传递给maven来跳过javadoc生成。