7-hadoop的运行模式（完全分布式）（中）

1、集群配置

1、集群的规划

三台机器进行相关的不同的部署

注意：
NameNode和SecondaryNameNode占用内存是1：1，要求他俩不在一个节点上。

ResourceManager是整个资源管理器的龙头需要避开NameNode和SeconddarynameNode

2、配置集群

hadoop2配置
1、核心配置文件（core-site.xml）

<configuration> 
　　<!-- 指定HDFS中NameNode的地址 --> 
　　<property> 
　　<name>fs.defaultFS</name> 
　　<value>hdfs://hadoop2:9000</value> 
</property> 

<!-- 指定Hadoop运行时产生文件的存储目录 -->
<property> 
　　<name>hadoop.tmp.dir</name>  
　　<value>/opt/module/hadoop-2.7.2/data/tmp</value>   
</configuration>

2、HDFS配置文件
hadoop-env.sh

# The java implementation to use. 
export JAVA_HOME=/opt/jdk1.8.0_131

hdfs-site.xml

<configuration> 
　　<property> 
　　　　<name>dfs.replication</name> 
　　　　<value>3</value> 
　　</property> 

　　<!-- 指定Hadoop辅助名称节点主机配置 --> 
　　<property> 
　　　　<name>dfs.namenode.secondary.http-address</name> 
　　　　<value>hadoop4:50090</value> 
　　</property> 
</configuration>

3、yarn配置文件

配置yarn-env.sh的java环境变量

# some Java parameters 
export JAVA_HOME=/opt/jdk1.8.0_131

配置yarn-site.xml

<!-- Reducer获取数据的方式 --> 
<property>       
　　<name>yarn.nodemanager.aux-services</name>       
　　<value>mapreduce_shuffle</value> 
</property> 

<!-- 指定YARN的ResourceManager的地址 --> 
<property>       
　　<name>yarn.resourcemanager.hostname</name>       
　　<value>hadoop3</value> 
</property>

4、MapReduce配置文件

配置mapred-env.sh的java环境变量

export JAVA_HOME=export JAVA_HOME=/opt/jdk1.8.0_131

配置mapred-site.xml

使用命令进行重命名
mv mapred-site.xml.template mapred-site.xml

进行配置

<configuration> 
<!-- 指定MR运行在Yarn上 -->
　　<property> 
　　　　<name>mapreduce.framework.name</name> 
　　　　<value>yarn</value> 
　　</property> 
</configuration>

5、进行同部

[root@hadoop2 hadoop]# xsync /opt/module/hadoop-2.7.2/

fname=hadoop-2.7.2 
pdir=/opt/module 
------------------- hadoop3 -------------- 
root@hadoop3's password: 
sending incremental file list
 hadoop-2.7.2/etc/hadoop/core-site.xml 
hadoop-2.7.2/etc/hadoop/hadoop-env.sh 
hadoop-2.7.2/etc/hadoop/hdfs-site.xml 
hadoop-2.7.2/etc/hadoop/mapred-env.sh 
hadoop-2.7.2/etc/hadoop/mapred-site.xml 
hadoop-2.7.2/etc/hadoop/yarn-env.sh 
hadoop-2.7.2/etc/hadoop/yarn-site.xml 

sent 29,961 bytes received 391 bytes 5,518.55 bytes/sec 
total size is 249,336,011 speedup is 8,214.81 
------------------- hadoop4 -------------- 
root@hadoop4's password:
sending incremental file list 
hadoop-2.7.2/etc/hadoop/core-site.xml 
hadoop-2.7.2/etc/hadoop/hadoop-env.sh 
hadoop-2.7.2/etc/hadoop/hdfs-site.xml 
hadoop-2.7.2/etc/hadoop/mapred-env.sh 
hadoop-2.7.2/etc/hadoop/mapred-site.xml 
hadoop-2.7.2/etc/hadoop/yarn-env.sh 
hadoop-2.7.2/etc/hadoop/yarn-site.xml 
sent 29,961 bytes received 391 bytes 3,570.82 bytes/sec 
total size is 249,336,011 speedup is 8,214.81

2、集群单点启动

1、如果集群是第一次启动，需要格式化NameNode

[root@hadoop2 hadoop-2.7.2]# bin/hdfs namenode -format

2、分别启动节点
hadoop2上

[root@hadoop2 hadoop-2.7.2]# sbin/hadoop-daemon.sh start namenode 
starting namenode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-namenode-hadoop2.out 
[root@hadoop2 hadoop-2.7.2]# sbin/hadoop-daemon.sh start datanode 
starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop2.out 
[root@hadoop2 hadoop-2.7.2]# jps 
3778 Jps 
3621 NameNode 
3706 DataNode 
[root@hadoop2 hadoop-2.7.2]#

hadoop3

[root@hadoop3 hadoop-2.7.2]# sbin/hadoop-daemon.sh start 
datanode starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop3.out 
[root@hadoop3 hadoop-2.7.2]# jps 
3652 DataNode 
3688 Jps 
[root@hadoop3 hadoop-2.7.2]#

hadoop4

[root@hadoop4 hadoop-2.7.2]# sbin/hadoop-daemon.sh start 
datanode starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop4.out
[root@hadoop4 hadoop-2.7.2]# jps 
3256 DataNode 
3292 Jps
[root@hadoop4 hadoop-2.7.2]#

注意：在hadoop102、hadoop103以及hadoop104上分别启动DataNode

思考：每次都一个一个节点启动，如果节点数增加到1000个怎么办？

此时需要使用ssh无密码登陆配置

3、SSH无密码登陆配置

小演示：

[root@hadoop2 hadoop-2.7.2]# ssh hadoop3 
root@hadoop3's password: 
Last login: Sun Jul 21 04:34:06 2019 from desktop-shrmqh1 
[root@hadoop3 ~]# hostname 
hadoop3 
[root@hadoop3 ~]# 
[root@hadoop3 ~]# 
[root@hadoop3 ~]# exit

免密登陆原理：

hadoop1

[root@hadoop2 ~]# cd .ssh/ 
[root@hadoop2 .ssh]# pwd 
/root/.ssh

进行生成密钥

[root@hadoop2 .ssh]# ssh-keygen -t rsa 
Generating public/private rsa key pair. 
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /root/.ssh/id_rsa. 
Your public key has been saved in /root/.ssh/id_rsa.pub. 
The key fingerprint is: 
SHA256:Qet88Bq/J/ko+1MQYjHxAOeGKOwczVFu3Z8gg+Pf5Qk root@hadoop2 
The key's randomart image is: 
+---[RSA 2048]----+
| ..o.Bo | 
| . o + Bo*. | 
| + + *.X.+. | 
| o o o = *.o . | 
| o . S E.+ | 
| . * +.. | 
| o ooo | 
| . +o. | 
| .++=. | 
+----[SHA256]-----+

查看生成的公钥和私钥

[root@hadoop2 .ssh]# ll 
total 12 
-rw-------. 1 root root 1675 Jul 21 05:54 id_rsa 
-rw-r--r--. 1 root root 394 Jul 21 05:54 id_rsa.pub 
-rw-r--r--. 1 root root 367 Jul 21 03:17 known_hosts

进行拷贝id到hadoop3、hadoop4

[root@hadoop2 ~]# ssh-copy-id hadoop3 
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub" 
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed 
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys 
root@hadoop3's password: 
Number of key(s) added: 1 
Now try logging into the machine, with: "ssh 'hadoop3'" 
and check to make sure that only the key(s) you wanted were added.

同时还要拷贝到自身

注意：

还需要在hadoop2上采用root账号，配置一下无密登录到hadoop2、hadoop3、hadoop4；

还需要在hadoop3上采用其他账号配置一下无密登录到hadoop2、hadoop3、hadoop4服务器上

注意：hadoop3也需要进行生工公钥和私钥
因为该机器上又ResourceManager，然后进行hadoop2、hadoop4上进行拷贝

.ssh文件夹下（~/.ssh)的文件功能解释

4、群起集群

1、配置slaves

不允许有空格，不允许有空行

其他两台机器进行分发

[root@hadoop2 hadoop]# xsync slaves

2、启动集群

（1）如果集群是第一次启动，需要格式化NameNode（注意格式化之前，一定要先停止上次启动的所有namenode和datanode进程，然后再删除data和log数据）
bin/hdfs namenode -format

（2）启动HDFS（包括namenode和datanode）
命令：[root@hadoop2 hadoop-2.7.2]# sbin/start-dfs.sh

[root@hadoop2 hadoop-2.7.2]# sbin/start-dfs.sh 
Starting namenodes on [hadoop2]
hadoop2: starting namenode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-namenode-hadoop2.out
hadoop2: starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop2.out
hadoop3: starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop3.out
hadoop4: starting datanode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-datanode-hadoop4.out
Starting secondary namenodes [hadoop4]
hadoop4: starting secondarynamenode, logging to /opt/module/hadoop-2.7.2/logs/hadoop-root-secondarynamenode-hadoop4.out

此时需要要进行对比

（3）启动YARN
注意：NameNode和ResourceManger如果不是同一台机器，不能在NameNode上启动
YARN，应该在ResouceManager所在的机器上启动YARN。

hadoop3上进行启动

[root@hadoop3 hadoop-2.7.2]# sbin/start-yarn.sh

[root@hadoop3 hadoop-2.7.2]# sbin/start-yarn.sh 
starting yarn daemons 
resourcemanager running as process 4249. Stop it first. 
hadoop2: starting nodemanager, logging to /opt/module/hadoop-2.7.2/logs/yarn-root-nodemanager-hadoop2.out 
hadoop3: starting nodemanager, logging to /opt/module/hadoop-2.7.2/logs/yarn-root-nodemanager-hadoop3.out 
hadoop4: starting nodemanager, logging to /opt/module/hadoop-2.7.2/logs/yarn-root-nodemanager-hadoop4.out