Hadoop集群部署流程

前置要求

需要3台虚拟机，系统为Centos7，分别host命名为node1，node2，node3，密码均为root
请确保这三台虚拟机已经完成了JDK、SSH免密、关闭防火墙、配置主机名映射等前置操作

在3台虚拟机的/etc/hosts文件中，填入如下内容：（同时这也是三台虚拟机的ip地址）

192.168.88.131 node1
192.168.88.132 node2
192.168.88.133 node3

请在VMware中，对：

node1设置4GB或以上内存
node2和node3设置2GB或以上内存

大数据的软件本身就是集群化（一堆服务器）一起运行的。

现在我们在一台电脑中以多台虚拟机来模拟集群，确实会有很大的内存压力哦。

角色分配如下：

node1:Namenode、Datanode、ResourceManager、NodeManager、HistoryServer、WebProxyServer、QuorumPeerMain
node2:Datanode、NodeManager、QuorumPeerMain
node3:Datanode、NodeManager、QuorumPeerMain

Hadoop集群部署

下载Hadoop安装包、解压、配置软链接

# 1. 下载
wget http://archive.apache.org/dist/hadoop/common/hadoop-3.3.0/hadoop-3.3.0.tar.gz# 2. 解压
# 请确保目录/export/server存在
tar -zxvf hadoop-3.3.0.tar.gz -C /export/server/# 3. 构建软链接
ln -s /export/server/hadoop-3.3.0 /export/server/hadoop

修改配置文件：hadoop-env.sh

Hadoop的配置文件要修改的地方很多，请细心

cd 进入到/export/server/hadoop/etc/hadoop，文件夹中，配置文件都在这里

修改hadoop-env.sh文件

此文件是配置一些Hadoop用到的环境变量

这些是临时变量，在Hadoop运行时有用

如果要永久生效，需要写到/etc/profile中

# 在文件开头加入：
# 配置Java安装路径
export JAVA_HOME=/export/server/jdk
# 配置Hadoop安装路径
export HADOOP_HOME=/export/server/hadoop
# Hadoop hdfs配置文件路径
export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop
# Hadoop YARN配置文件路径
export YARN_CONF_DIR=$HADOOP_HOME/etc/hadoop
# Hadoop YARN 日志文件夹
export YARN_LOG_DIR=$HADOOP_HOME/logs/yarn
# Hadoop hdfs 日志文件夹
export HADOOP_LOG_DIR=$HADOOP_HOME/logs/hdfs# Hadoop的使用启动用户配置
export HDFS_NAMENODE_USER=root
export HDFS_DATANODE_USER=root
export HDFS_SECONDARYNAMENODE_USER=root
export YARN_RESOURCEMANAGER_USER=root
export YARN_NODEMANAGER_USER=root
export YARN_PROXYSERVER_USER=root

修改配置文件：core-site.xml

如下，清空文件，填入如下内容

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--Licensed under the Apache License, Version 2.0 (the "License");you may not use this file except in compliance with the License.You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed under the License is distributed on an "AS IS" BASIS,WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.See the License for the specific language governing permissions andlimitations under the License. See accompanying LICENSE file.
--><!-- Put site-specific property overrides in this file. -->
<configuration><property><name>fs.defaultFS</name><value>hdfs://node1:8020</value><description></description></property><property><name>io.file.buffer.size</name><value>131072</value><description></description></property>
</configuration>

配置：hdfs-site.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--Licensed under the Apache License, Version 2.0 (the "License");you may not use this file except in compliance with the License.You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed under the License is distributed on an "AS IS" BASIS,WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.See the License for the specific language governing permissions andlimitations under the License. See accompanying LICENSE file.
--><!-- Put site-specific property overrides in this file. --><configuration><property><name>dfs.datanode.data.dir.perm</name><value>700</value></property><property><name>dfs.namenode.name.dir</name><value>/data/nn</value><description>Path on the local filesystem where the NameNode stores the namespace and transactions logs persistently.</description></property><property><name>dfs.namenode.hosts</name><value>node1,node2,node3</value><description>List of permitted DataNodes.</description></property><property><name>dfs.blocksize</name><value>268435456</value><description></description></property><property><name>dfs.namenode.handler.count</name><value>100</value><description></description></property><property><name>dfs.datanode.data.dir</name><value>/data/dn</value></property>
</configuration>

配置：mapred-env.sh文件

# 在文件的开头加入如下环境变量设置
export JAVA_HOME=/export/server/jdk
export HADOOP_JOB_HISTORYSERVER_HEAPSIZE=1000
export HADOOP_MAPRED_ROOT_LOGGER=INFO,RFA

配置：mapred-site.xml文件

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--Licensed under the Apache License, Version 2.0 (the "License");you may not use this file except in compliance with the License.You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed under the License is distributed on an "AS IS" BASIS,WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.See the License for the specific language governing permissions andlimitations under the License. See accompanying LICENSE file.
--><!-- Put site-specific property overrides in this file. --><configuration><property><name>mapreduce.framework.name</name><value>yarn</value><description></description></property><property><name>mapreduce.jobhistory.address</name><value>node1:10020</value><description></description></property><property><name>mapreduce.jobhistory.webapp.address</name><value>node1:19888</value><description></description></property><property><name>mapreduce.jobhistory.intermediate-done-dir</name><value>/data/mr-history/tmp</value><description></description></property><property><name>mapreduce.jobhistory.done-dir</name><value>/data/mr-history/done</value><description></description></property>
<property><name>yarn.app.mapreduce.am.env</name><value>HADOOP_MAPRED_HOME=$HADOOP_HOME</value>
</property>
<property><name>mapreduce.map.env</name><value>HADOOP_MAPRED_HOME=$HADOOP_HOME</value>
</property>
<property><name>mapreduce.reduce.env</name><value>HADOOP_MAPRED_HOME=$HADOOP_HOME</value>
</property>
</configuration>

配置：yarn-env.sh文件

# 在文件的开头加入如下环境变量设置
export JAVA_HOME=/export/server/jdk
export HADOOP_HOME=/export/server/hadoop
export HADOOP_CONF_DIR=$HADOOP_HOME/etc/hadoop
export YARN_CONF_DIR=$HADOOP_HOME/etc/hadoop
export YARN_LOG_DIR=$HADOOP_HOME/logs/yarn
export HADOOP_LOG_DIR=$HADOOP_HOME/logs/hdfs

配置：yarn-site.xml文件

<?xml version="1.0"?>
<!--Licensed under the Apache License, Version 2.0 (the "License");you may not use this file except in compliance with the License.You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, softwaredistributed under the License is distributed on an "AS IS" BASIS,WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.See the License for the specific language governing permissions andlimitations under the License. See accompanying LICENSE file.
-->
<configuration><!-- Site specific YARN configuration properties -->
<property><name>yarn.log.server.url</name><value>http://node1:19888/jobhistory/logs</value><description></description>
</property><property><name>yarn.web-proxy.address</name><value>node1:8089</value><description>proxy server hostname and port</description></property><property><name>yarn.log-aggregation-enable</name><value>true</value><description>Configuration to enable or disable log aggregation</description></property><property><name>yarn.nodemanager.remote-app-log-dir</name><value>/tmp/logs</value><description>Configuration to enable or disable log aggregation</description></property><!-- Site specific YARN configuration properties --><property><name>yarn.resourcemanager.hostname</name><value>node1</value><description></description></property><property><name>yarn.resourcemanager.scheduler.class</name><value>org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler</value><description></description></property><property><name>yarn.nodemanager.local-dirs</name><value>/data/nm-local</value><description>Comma-separated list of paths on the local filesystem where intermediate data is written.</description></property><property><name>yarn.nodemanager.log-dirs</name><value>/data/nm-log</value><description>Comma-separated list of paths on the local filesystem where logs are written.</description></property><property><name>yarn.nodemanager.log.retain-seconds</name><value>10800</value><description>Default time (in seconds) to retain log files on the NodeManager Only applicable if log-aggregation is disabled.</description></property><property><name>yarn.nodemanager.aux-services</name><value>mapreduce_shuffle</value><description>Shuffle service that needs to be set for Map Reduce applications.</description></property>
</configuration>

修改workers文件
```
# 全部内容如下
node1
node2
node3
```
分发hadoop到其它机器

# 在node1执行
cd /export/serverscp -r hadoop-3.3.0 node2:`pwd`/
scp -r hadoop-3.3.0 node3:`pwd`/

在node2、node3执行

# 创建软链接
ln -s /export/server/hadoop-3.3.0 /export/server/hadoop

创建所需目录

在node1执行：

mkdir -p /data/nn
mkdir -p /data/dn
mkdir -p /data/nm-log
mkdir -p /data/nm-local

在node2执行：

mkdir -p /data/dn
mkdir -p /data/nm-log
mkdir -p /data/nm-local

在node3执行：

mkdir -p /data/dn
mkdir -p /data/nm-log
mkdir -p /data/nm-local

配置环境变量

在node1、node2、node3修改/etc/profile

export HADOOP_HOME=/export/server/hadoop
export PATH=$PATH:$HADOOP_HOME/bin:$HADOOP_HOME/sbin

执行source /etc/profile生效

格式化NameNode，在node1执行
```
hadoop namenode -format
```
hadoop这个命令来自于：$HADOOP_HOME/bin中的程序

由于配置了环境变量PATH，所以可以在任意位置执行hadoop命令哦
启动hadoop的hdfs集群，在node1执行即可
```
start-dfs.sh# 如需停止可以执行
stop-dfs.sh
```
start-dfs.sh这个命令来自于：$HADOOP_HOME/sbin中的程序

由于配置了环境变量PATH，所以可以在任意位置执行start-dfs.sh命令哦

启动hadoop的yarn集群，在node1执行即可

start-yarn.sh# 如需停止可以执行
stop-yarn.sh

启动历史服务器

mapred --daemon start historyserver# 如需停止将start更换为stop

启动web代理服务器

yarn-daemon.sh start proxyserver# 如需停止将start更换为stop

验证Hadoop集群运行情况

在node1、node2、node3上通过jps验证进程是否都启动成功
验证HDFS，浏览器打开：http://node1:9870

创建文件test.txt，随意填入内容，并执行：
```
hadoop fs -put test.txt /test.txthadoop fs -cat /test.txt
```

验证YARN，浏览器打开：http://node1:8088

执行：

# 创建文件words.txt，填入如下内容
example osc hadoop
osc hadoop hadoop
osc hadoop# 将文件上传到HDFS中
hadoop fs -put words.txt /words.txt# 执行如下命令验证YARN是否正常
hadoop jar /export/server/hadoop/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.3.0.jar wordcount -Dmapred.job.queue.name=root.root /words.txt /output

在web界面能看到任务并且没有报错，则集群部署成功！