一、概述

概念：

是一个可靠的、可伸缩的、分布式计算的开源软件。
是一个框架，允许跨越计算机集群的大数据及分布式处理，使用简单的编程模型（mapreduce）
可从单台服务器扩展至几千台主机，每个节点提供了计算和存储功能。
不依赖于硬件处理HA，在应用层面实现

特性4V：

volumn 体量大
velocity 速度快
variaty 样式多
value 价值密度低

模块：

hadoop common 公共类库，支持其他模块
HDFS hadoop distributed file system，hadoop分布式文件系统
Hadoop yarn 作业调度和资源管理框架
hadoop mapreduce 基于yarn系统的大数据集并行处理技术。

二、安装部署

2.1 主机规划

主机名称	IP地址	安装节点应用
hadoop-1	172.20.2.203	namenode/datanode/nodemanager
hadoop-2	172.20.2.204	secondarynode/datanode/nodemanager
hadoop-3	172.20.2.205	resourcemanager/datanode/nodemanager

2.2 部署

2.2.1 基础环境配置

a.配置java环境

yum install java-1.8.0-openjdk.x86_64 java-1.8.0-openjdk-devel -y
cat >/etc/profile.d/java.sh<<EOF
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.161-3.b14.el6_9.x86_64
export CLASSPATH=.:\$JAVA_HOME/jre/lib/rt.jar:\$JAVA_HOME/lib/dt.jar:\$JAVA_HOME/lib/tools.jar 
export PATH=\$PATH:\$JAVA_HOME/bin
EOF
source /etc/profile.d/java.sh

b.修改主机名添加hosts

hostname hadoop-1
cat >>/etc/hosts<<EOF
172.20.2.203    hadoop-1
172.20.2.204    hadoop-2
172.20.2.205    hadoop-3
EOF

c.创建用户及目录

useradd hadoop
echo "hadoopwd" |passwd hadoop --stdin
mkdir -pv /data/hadoop/hdfs/{nn,snn,dn}
chown -R hadoop:hadoop /data/hadoop/hdfs/
mkdir -p /var/log/hadoop/yarn
mkdir -p /dbapps/hadoop/logs
chmod g+w /dbapps/hadoop/logs/
chown -R hadoop.hadoop /dbapps/hadoop/

d.配置hadoop环境变量

cat>/etc/profile.d/hadoop.sh<<EOF
export HADOOP_PREFIX=/usr/local/hadoop
export PATH=\$PATH:\$HADOOP_PREFIX/bin:\$HADOOP_PREFIX/sbin
export HADOOP_COMMON_HOME=\${HADOOP_PREFIX}
export HADOOP_HDFS_HOME=\${HADOOP_PREFIX}
export HADOOP_MAPRED_HOME=\${HADOOP_PREFIX}
export HADOOP_YARN_HOME=\${HADOOP_PREFIX}
EOF
source /etc/profile.d/hadoop.sh

e.下载并解压软件包

mkdir /software 
cd /software 
wget -c http://www.apache.org/dyn/closer.cgi/hadoop/common/hadoop-2.7.5/hadoop-2.7.5.tar.gz
tar -zxf hadoop-2.6.5.tar.gz -C /usr/local
ln -sv /usr/local/hadoop-2.6.5/ /usr/local/hadoop
chown hadoop.hadoop /usr/local/hadoop-2.6.5/ -R

f.hadoop用户免密钥配置

su - hadoop
ssh-keygen -t rsa
for num in `seq 1 3`;do ssh-copy-id -i /home/hadoop/.ssh/id_rsa.pub hadoop@hadoop-$num;done

2.3 配置hadoop

2.3.1 配置各节点

配置master节点

hadoop-1节点运行namenode/datanode/nodemanager,修改hadoop-1的hadoop配置文件

core-site.xml（定义namenode节点）

cat>/usr/local/hadoop/etc/hadoop/core-site.xml <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://hadoop-1:8020</value>
<final>true</final>
</property>
</configuration>
EOF

hdfs-site.xml修改replication为data节点数目 （定义secondary节点）

cat >/usr/local/hadoop/etc/hadoop/hdfs-site.xml <<EOF
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>dfs.namenode.secondary.http-address</name>
<value>hadoop-2:50090</value>
</property>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
<property>
<name>dfs.namenode.name.dir</name>
<value>file:///data/hadoop/hdfs/nn</value>
</property>
<property>
<name>dfs.datanode.data.dir</name>
<value>file:///data/hadoop/hdfs/dn</value>
</property>
<property>
<name>fs.checkpoint.dir</name>
<value>file:///data/hadoop/hdfs/snn</value>
</property>
<property>
<name>fs.checkpoint.edits.dir</name>
<value>file:///data/hadoop/hdfs/snn</value>
</property>
</configuration>
EOF

添加mapred-site.xml

cat >/usr/local/hadoop/etc/hadoop/mapred-site.xml <<EOF
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>
EOF

yarn-site.xml修改对应values为master的主机名（定义resourcemanager节点）

cat >/usr/local/hadoop/etc/hadoop/yarn-site.xml<<EOF
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>yarn.resourcemanager.address</name>
<value>hadoop-3:8032</value>
</property>
<property>
<name>yarn.resourcemanager.scheduler.address</name>
<value>hadoop-3:8030</value>
</property>
<property>
<name>yarn.resourcemanager.resource-tracker.address</name>
<value>hadoop-3:8031</value>
</property>
<property>
<name>yarn.resourcemanager.admin.address</name>
<value>hadoop-3:8033</value>
</property>
<property>
<name>yarn.resourcemanager.webapp.address</name>
<value>hadoop-3:8088</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
<property>
<name>yarn.nodemanager.auxservices.mapreduce_shuffle.class</name>
<value>org.apache.hadoop.mapred.ShuffleHandler</value>
</property>
<property>
<name>yarn.resourcemanager.scheduler.class</name>
<value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler</value>
</property>
</configuration>
EOF

slaves(定义数据节点)

cat >/usr/local/hadoop/etc/hadoop/slaves<<EOF
hadoop-1
hadoop-2
hadoop-3
EOF

同样的步骤操作hadoop-2/3，建议将hadoop-1的文件直接分发至hadoop-2/3

2.3.2 格式化namenode

在NameNode机器上（hadoop-1）执行格式化：

hdfs namenode -format

2.3.3 启动服务

在namenode hadoop-1执行start-all.sh启动服务
在hadoop-3启动resourcemanager服务

hadoop-2服务查看

hadoop-3服务查看

2.3.4 运行测试程序

yarn jar /usr/local/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.6.5.jar pi 2 10

2.3.5 查看web界面

HDFS-NameNode

url:http://172.20.2.203:50070

YARN-ResourceManager

url:http://172.20.2.205:8088