hadoop动态添加删除节点datanode及恢复

2022-06-26 01:00:30

1. 配置系统环境

主机名,ssh互信,环境变量等

本文略去jdk安装，请将datanode的jdk安装路径与/etc/hadoop/hadoop-evn.sh中的java_home保持一致，版本hadoop2.7.5

修改/etc/sysconfig/network

然后执行命令
hostname 主机名
这个时候可以注销一下系统，再重登录之后就行了

[root@localhost ~]# hostname

localhost.localdomain

[root@localhost ~]# hostname -i

:: 127.0.0.1

[root@localhost ~]#

[root@localhost ~]# cat /etc/sysconfig/network

# Created by anaconda

NETWORKING=yes

HOSTNAME=slave2

GATEWAY=192.168.48.2

# oracle-rdbms-server-11gR2-preinstall : Add NOZEROCONF=yes

NOZEROCONF=yes

[root@localhost ~]# hostname slave2

[root@localhost ~]# hostname

slave2

[root@localhost ~]# su - hadoop

Last login: Sat Feb  :: CST  on pts/

[hadoop@slave2 ~]$ su - root

建datanode目录并改所有者

（此处的具体路径值，请参照namenode中/usr/hadoop/hadoop-2.7.5/etc/hadoop/hdfs-site.xml,core-site.xml中的dfs.name.dir，dfs.data.dir,dfs.tmp.dir等）

Su - root

# mkdir -p /usr/local/hadoop-2.7.5/tmp/dfs/data

# chmod -R 777 /usr/local/hadoop-2.7.5/tmp

# chown -R hadoop:hadoop /usr/local/hadoop-2.7.5

[root@slave2 ~]# mkdir -p /usr/local/hadoop-2.7./tmp/dfs/data

[root@slave2 ~]# chmod -R  /usr/local/hadoop-2.7./tmp

 [root@slave2 ~]# chown -R hadoop:hadoop /usr/local/hadoop-2.7.

 [root@slave2 ~]# pwd

/root

[root@slave2 ~]# cd /usr/local/

[root@slave2 local]# ll

total

drwxr-xr-x.  root   root    Mar    bin

drwxr-xr-x.  root   root     Jun    etc

drwxr-xr-x.  root   root     Jun    games

drwxr-xr-x   hadoop hadoop  Feb  : hadoop-2.7.

drwxr-xr-x.  root   root     Jun    include

drwxr-xr-x.  root   root     Jun    lib

drwxr-xr-x.  root   root     Jun    lib64

drwxr-xr-x.  root   root     Jun    libexec

drwxr-xr-x.  root   root     Jun    sbin

drwxr-xr-x.  root   root    Dec    share

drwxr-xr-x.  root   root     Jun    src

[root@slave2 local]#

ssh互信，即实现 master-->slave2免密码

master:

[root@hadoop-master ~]# cat /etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4

::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

192.168.48.129    hadoop-master

192.168.48.132    slave1

192.168.48.131    slave2

[hadoop@hadoop-master ~]$ scp /usr/hadoop/.ssh/authorized_keys hadoop@slave2:/usr/hadoop/.ssh

The authenticity of host 'slave2 (192.168.48.131)' can't be established.

ECDSA key fingerprint is 1e:cd:d1:3d:b0:5b:62:45:a3:63:df:c7:7a:0f:b8:7c.

Are you sure you want to continue connecting (yes/no)? yes

Warning: Permanently added 'slave2,192.168.48.131' (ECDSA) to the list of known hosts.

hadoop@slave2's password:

authorized_keys

[hadoop@hadoop-master ~]$ ssh hadoop@slave2

Last login: Sat Feb 24 18:27:33 2018

[hadoop@slave2 ~]$

[hadoop@slave2 ~]$ exit

logout

Connection to slave2 closed.

[hadoop@hadoop-master ~]$

2. 修改namenode节点的slave文件,增加新节点信息

[hadoop@hadoop-master hadoop]$ pwd

/usr/hadoop/hadoop-2.7.5/etc/hadoop

[hadoop@hadoop-master hadoop]$ vi slaves

slave1

slave2

3. 在namenode节点上,将hadoop-2.7.3复制到新节点上,并在新节点上删除data和logs目录中的文件

Master

[hadoop@hadoop-master ~]$ scp -R hadoop-2.7.5 hadoop@slave2:/usr/hadoop

Slave2

[hadoop@slave2 hadoop-2.7.5]$ ll

total 124

drwxr-xr-x 2 hadoop hadoop  4096 Feb 24 14:29 bin

drwxr-xr-x 3 hadoop hadoop    19 Feb 24 14:30 etc

drwxr-xr-x 2 hadoop hadoop   101 Feb 24 14:30 include

drwxr-xr-x 3 hadoop hadoop    19 Feb 24 14:29 lib

drwxr-xr-x 2 hadoop hadoop  4096 Feb 24 14:29 libexec

-rw-r--r-- 1 hadoop hadoop 86424 Feb 24 18:44 LICENSE.txt

drwxrwxr-x 2 hadoop hadoop  4096 Feb 24 14:30 logs

-rw-r--r-- 1 hadoop hadoop 14978 Feb 24 18:44 NOTICE.txt

-rw-r--r-- 1 hadoop hadoop  1366 Feb 24 18:44 README.txt

drwxr-xr-x 2 hadoop hadoop  4096 Feb 24 14:29 sbin

drwxr-xr-x 4 hadoop hadoop    29 Feb 24 14:30 share

[hadoop@slave2 hadoop-2.7.5]$ pwd

/usr/hadoop/hadoop-2.7.5

[hadoop@slave2 hadoop-2.7.5]$ rm -R logs/*

4. 启动新datanode的datanode和nodemanger进程

先确认namenode和当前的datanode中，etc/hoadoop/excludes文件中无待加入的主机，再进行下面操作

[hadoop@slave2 hadoop-2.7.]$ sbin/hadoop-daemon.sh start datanode

starting datanode, logging to /usr/hadoop/hadoop-2.7./logs/hadoop-hadoop-datanode-slave2.out

[hadoop@slave2 hadoop-2.7.]$ sbin/yarn-daemon.sh start nodemanager

starting datanode, logging to /usr/hadoop/hadoop-2.7./logs/yarn-hadoop-datanode-slave2.out

[hadoop@slave2 hadoop-2.7.]$

[hadoop@slave2 hadoop-2.7.]$ jps

 DataNode

 NodeManager

 Jps

[hadoop@slave2 ~]$

5、在NameNode上刷新节点

[hadoop@hadoop-master ~]$ hdfs dfsadmin -refreshNodes

Refresh nodes successful

[hadoop@hadoop-master ~]$sbin/start-balancer.sh

6. 在namenode查看当前集群情况,

确认节点已经正常加入

[hadoop@hadoop-master hadoop]$ hdfs dfsadmin -report

Configured Capacity:  (54.63 GB)

Present Capacity:  (14.42 GB)

DFS Remaining:  (14.42 GB)

DFS Used:  ( KB)

DFS Used%: 0.00%

Under replicated blocks:

Blocks with corrupt replicas:

Missing blocks:

Missing blocks (with replication factor ): 

-------------------------------------------------

Live datanodes (2):

Name: 192.168.48.131:50010 (slave2)

Hostname: 183.221.250.11

Decommission Status : Normal

Configured Capacity: 38588669952 (35.94 GB)

DFS Used: 8192 (8 KB)

Non DFS Used: 36887191552 (34.35 GB)

DFS Remaining: 1701470208 (1.58 GB)

DFS Used%: 0.00%

DFS Remaining%: 4.41%

Configured Cache Capacity: 0 (0 B)

Cache Used: 0 (0 B)

Cache Remaining: 0 (0 B)

Cache Used%: 100.00%

Cache Remaining%: 0.00%

Xceivers: 1

Last contact: Thu Mar 01 19:36:33 PST 2018

Name: 192.168.48.132: (slave1)

Hostname: slave1

Decommission Status : Normal

Configured Capacity:  (18.70 GB)

DFS Used:  ( KB)

Non DFS Used:  (5.86 GB)

DFS Remaining:  (12.84 GB)

DFS Used%: 0.00%

DFS Remaining%: 68.67%

Configured Cache Capacity:  ( B)

Cache Used:  ( B)

Cache Remaining:  ( B)

Cache Used%: 100.00%

Cache Remaining%: 0.00%

Xceivers:

Last contact: Thu Mar  :: PST 

[hadoop@hadoop-master hadoop]$

7动态删除datanode

7.1配置NameNode的hdfs-site.xml，

适当减小dfs.replication副本数，增加dfs.hosts.exclude配置

[hadoop@hadoop-master hadoop]$ pwd

/usr/hadoop/hadoop-2.7./etc/hadoop

[hadoop@hadoop-master hadoop]$ cat hdfs-site.xml

<configuration>

<property>

      <name>dfs.replication</name>

      <value></value>

</property>

  <property>

      <name>dfs.name.dir</name>

      <value>/usr/local/hadoop-2.7./tmp/dfs/name</value>

</property>

    <property>

      <name>dfs.data.dir</name>

      <value>/usr/local/hadoop-2.7./tmp/dfs/data</value>

    </property>

<property>

    <name>dfs.hosts.exclude</name>

    <value>/usr/hadoop/hadoop-2.7.5/etc/hadoop/excludes</value>

  </property>

</configuration>

7.2在namenode对应路径（/etc/hadoop/）下新建excludes文件，

并写入待删除DataNode的ip或域名

[hadoop@hadoop-master hadoop]$ pwd
/usr/hadoop/hadoop-2.7.5/etc/hadoop
[hadoop@hadoop-master hadoop]$ vi excludes

####slave2

192.168.48.131[hadoop@hadoop-master hadoop]$

7.3在NameNode上刷新所有DataNode

hdfs dfsadmin -refreshNodes

sbin/start-balancer.sh

7.4在namenode查看当前集群情况,

确认信节点已经正常删除,结果中已无slave2

[hadoop@hadoop-master hadoop]$ hdfs dfsadmin -report

或者可以在web检测界面（ip:50070）上可以观测到DataNode逐渐变为Dead。

http://192.168.48.129:50070/

在datanode项,Admin state已经由“In Service“变为”Decommissioned“，则表示删除成功
hadoop动态添加删除节点datanode及恢复hadoop动态添加删除节点datanode及恢复

7.5停止已删除的节点相关进程

[hadoop@slave2 hadoop-2.7.]$ jps

 Jps

 DataNode

 NodeManager

[hadoop@slave2 hadoop-2.7.]$ sbin/hadoop-daemon.sh stop datanode

stopping datanode

[hadoop@slave2 hadoop-2.7.]$ sbin/yarn-daemon.sh stop nodemanager

stopping nodemanager

[hadoop@slave2 hadoop-2.7.]$ jps

 Jps

[hadoop@slave2 hadoop-2.7.]$

8恢复已删除节点

执行7.2 中删除相关信息，然后4，5，6即可

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