centos7下hadoop

环境准备

在开始编译Hadoop 2.x之前，我们需要确保已经安装了以下软件包：

1、JDK 8(Java Development Kit)

2、Apache Maven 3.5.0(Java项目构建工具)

3、CMake(跨平台的自动化构建工具)

4、Git(版本控制工具)

5、wget和tar(用于下载和解压源码包)

下载源码包

我们需要从Apache Hadoop官网下载Hadoop 2.x的源码包，访问https://hadoop.apache.org/releases.htmlhadoop-2.x,选择合适的版本并下载对应的源码压缩包(如：hadoop-2.9.2.tar.gz)。

解压源码包

下载完成后，使用以下命令解压源码包：

tar -zxvf hadoop-2.9.2.tar.gz

配置环境变量

为了方便编译和运行Hadoop,我们需要配置一些环境变量，打开~/.bashrc文件，添加以下内容：

export HADOOP_HOME=/path/to/hadoop-2.9.2
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export HADOOP_OPTS="-Djava.library.path=$HADOOP_HOME/lib/native"

注意将/path/to/hadoop-2.9.2替换为实际的Hadoop解压路径，保存文件后，执行以下命令使配置生效：

source ~/.bashrc

编译Hadoop

接下来，我们将编译Hadoop 2.x，进入Hadoop源码目录：

cd $HADOOP_HOME

运行CMake以生成Makefile:

cmake -B build -H. -DFS_DEFAULT_NAMENODE_NAME="hdfs://localhost:9000" -DFS_DEFAULT_DATANODE_NAME="localhost:9001" -DBUILD_SLAVE=false -DBUILD_TESTING=false -DWITH_EXECUTOR=false -DWITH_MAPREDUCE=false -DWITH_PIG=false -DWITH_HADOOP_EXAMPLES=false -DWITH_MYSQL=false -DWITH_ARCHIVELOG=false -DWITH_COMPOSITE=false -DWITH_CLOUDERA=false -DWITH_HDFS_LIBCLUSTER=false -DWITH_NFS3=false -DWITH_YARN=true -DWITH_NODEMANAGER=true -DWITH_THRIFT=true -DWITH_ZOOKEEPER=true -DWITH_GCSH=true -DCMAKE_INSTALL_PREFIX=$HADOOP_HOME/build/hadoop-distine

这里的参数表示我们只编译YARN和NodeManager模块，根据需要，可以取消注释相应的参数来编译其他模块，编译完成后，执行以下命令进行编译：

make all -j$(nproc)

安装Hadoop

编译完成后，我们需要将编译好的库文件和可执行文件复制到指定的安装目录，执行以下命令：

sudo make install

配置环境变量(可选)

如果需要将Hadoop添加到系统的PATH环境变量中，可以在~/.bashrc文件中添加以下内容：

export HADOOP_HOME=/path/to/hadoop-2.9.2/build/hadoop-distine  根据实际情况修改路径
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin  将Hadoop的bin和sbin目录添加到PATH环境变量中

保存文件后，执行以下命令使配置生效：

source ~/.bashrc

相关问题与解答

1、如何查看Hadoop的版本信息？

答：可以通过执行以下命令查看Hadoop的版本信息：

echo $HADOOP_VERSION | tr '[:upper:]' '[:lower:]' && echo "=====================================" || true && mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | grep '<]*<' | tail -1 | sed 's/[^0-9\.]//g' || true && echo "=====================================" || true && cat $HADOOP_HOME/RELEASENOTES || true && exit 0; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this command"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this命令"; exit 1; false; echo "Please set the environment variable HADOOP_HOME to your Hadoop installation directory before running this命令"; exit