尚硅谷大数据技术之集群迁移（Apache和CDH）

1）准备两套集群，我这使用apache集群和CDH集群。

2）启动集群

3）启动完毕后，将apache集群中，hive库里dwd，dws，ads三个库的数据迁移到CDH集群

4）在apache集群里hosts加上CDH Namenode对应域名并分发给各机器

[root@hadoop101 ~]# vim /etc/hosts

[root@hadoop101 ~]# scp /etc/hosts hadoop102:/etc/                                                                                             

[root@hadoop101 ~]# scp /etc/hosts hadoop103:/etc/

5）因为集群都是HA模式，所以需要在apache集群上配置CDH集群,让distcp能识别出CDH的nameservice

[root@hadoop101 hadoop]# vim /opt/module/hadoop-3.1.3/etc/hadoop/hdfs-site.xml

<!–配置nameservice–>

<property>

  <name>dfs.nameservices</name>

  <value>mycluster,nameservice1</value>

</property>

<!–指定本地服务–>

<property>

  <name>dfs.internal.nameservices</name>

  <value>mycluster,nameservice1</value>

</property>

<!–配置多NamenNode–>

<property>

  <name>dfs.ha.namenodes.mycluster</name>

  <value>nn1,nn2,nn3</value>

</property>

<property>

  <name>dfs.namenode.rpc-address.mycluster.nn1</name>

  <value>hadoop101:8020</value>

</property>

<property>

<property>

  <name>dfs.namenode.rpc-address.mycluster.nn2</name>

  <value>hadoop102:8020</value>

</property>

<property>

  <name>dfs.namenode.rpc-address.mycluster.nn3</name>

  <value>hadoop103:8020</value>

</property>

<!–配置nameservice1的namenode服务–>

<property>

    <name>dfs.ha.namenodes.nameservice1</name>

    <value>namenode30,namenode37</value>

  </property>

 <property>

    <name>dfs.namenode.rpc-address.nameservice1.namenode30</name>

    <value>hadoop104:8020</value>

  </property>

<property>

    <name>dfs.namenode.rpc-address.nameservice1.namenode37</name>

    <value>hadoop106:8020</value>

  </property>

<property>

    <name>dfs.namenode.http-address.nameservice1.namenode30</name>

    <value>hadoop104:9870</value>

  </property>

  <property>

    <name>dfs.namenode.http-address.nameservice1.namenode37</name>

    <value>hadoop106:9870</value>

  </property>

  <property>

    <name>dfs.client.failover.proxy.provider.nameservice1</name>

    <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>

  </property>

<!–为NamneNode设置HTTP服务监听–>

<property>

  <name>dfs.namenode.http-address.mycluster.nn1</name>

  <value>hadoop101:9870</value>

</property>

<property>

  <name>dfs.namenode.http-address.mycluster.nn2</name>

  <value>hadoop102:9870</value>

</property>

<property>

  <name>dfs.namenode.http-address.mycluster.nn3</name>

  <value>hadoop103:9870</value>

</property>

<!–配置HDFS客户端联系Active NameNode节点的Java类–>

<property>

  <name>dfs.client.failover.proxy.provider.mycluster</name>

  <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>

</property>

6）修改CDH hosts

[root@hadoop101 ~]# vim /etc/hosts

7）进行分发，这里的hadoop104，hadoop105，hadoop106分别对应apache的hadoop101，hadoop102，hadoop103

[root@hadoop101 ~]# scp /etc/hosts hadoop102:/etc/

[root@hadoop101 ~]# scp /etc/hosts hadoop103:/etc/

8）同样修改CDH集群配置，在所有hdfs-site.xml文件里修改配置

<property>

    <name>dfs.nameservices</name>

    <value>mycluster,nameservice1</value>

</property>

<property>

    <name>dfs.internal.nameservices</name>

    <value>nameservice1</value>

</property>

<property>

    <name>dfs.ha.namenodes.mycluster</name>

    <value>nn1,nn2,nn3</value>

</property>

<property>

    <name>dfs.namenode.rpc-address.mycluster.nn1</name>

    <value>hadoop104:8020</value>

</property>

<property>

    <name>dfs.namenode.rpc-address.mycluster.nn2</name>

    <value>hadoop105:8020</value>

</property>

<property>

    <name>dfs.namenode.rpc-address.mycluster.nn3</name>

    <value>hadoop106:8020</value>

</property>

<property>

    <name>dfs.namenode.http-address.mycluster.nn1</name>

    <value>hadoop104:9870</value>

</property>

<property>

    <name>dfs.namenode.http-address.mycluster.nn2</name>

    <value>hadoop105:9870</value>

</property>

<property>

    <name>dfs.namenode.http-address.mycluster.nn3</name>

    <value>hadoop106:9870</value>

</property>

<property>

    <name>dfs.client.failover.proxy.provider.mycluster</name>

<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>

</property>

9）最后注意：重点由于我的Apahce集群和CDH集群3台集群都是hadoop101，hadoop102，hadoop103所以要关闭域名访问，使用IP访问

CDH把钩去了

10）apache设置为false

11）再使用hadoop distcp命令进行迁移，-Dmapred.job.queue.name指定队列，默认是default队列。上面配置集群都配了的话，那么在CDH和apache集群下都可以执行这个命令

[root@hadoop101 hadoop]# hadoop distcp -Dmapred.job.queue.name=hive  webhdfs://mycluster:9070/user/hive/warehouse/dwd.db/  hdfs://nameservice1/user/hive/warehouse

12）会启动一个MR任务，正在迁移

13）查看cdh 9870 http地址

14）数据已经成功迁移。数据迁移成功之后，接下来迁移hive表结构，编写shell脚本

[root@hadoop101 module]# vim exportHive.sh

#!/bin/bash

hive -e “use dwd;show tables”>tables.txt

cat tables.txt |while read eachline

do

hive -e “use dwd;show create table $eachline”>>tablesDDL.txt

echo “;” >> tablesDDL.txt

done

15）执行脚本后将tablesDDL.txt文件分发到CDH集群下

[root@hadoop101 module]# scp tablesDDL.txt  hadoop104:/opt/module/

16）然后CDH下导入此表结构，先进到CDH的hive里创建dwd库

[root@hadoop101 module]# hive

hive> create database dwd;

17）创建数据库后，边界tablesDDL.txt在最上方加上use dwd;

18）并且将createtab_stmt都替换成空格

[root@hadoop101 module]# sed -i s”#createtab_stmt# #g” tablesDDL.txt

19）最后执行hive -f命令将表结构导入

[root@hadoop101 module]# hive -f tablesDDL.txt

20）最后将表的分区重新刷新下，只有刷新分区才能把数据读出来，编写脚本

[root@hadoop101 module]# vim msckPartition.sh

#!/bin/bash

hive -e “use dwd;show tables”>tables.txt

cat tables.txt |while read eachline

do

hive -e “use dwd;MSCK REPAIR TABLE $eachline”

done

[root@hadoop101 module]# chmod +777 msckPartition.sh

[root@hadoop101 module]# ./msckPartition.sh

21）刷完分区后，查询表数据