hadoop删除节点

现在有hadoop1 ,hadoop2,hadoop3.hadoop4.

要删除hadoop4节点.

1）在namenode的/opt/module/hadoop-2.7.2/etc/hadoop目录下创建dfs.hosts.exclude文件

(hadoop1上)

[atguigu@hadoop1 hadoop]$ pwd

/opt/module/hadoop-2.7.2/etc/hadoop

[atguigu@hadoop1 hadoop]$ touch dfs.hosts.exclude

[atguigu@hadoop1 hadoop]$ vi dfs.hosts.exclude

添加如下主机名称（要退役的节点）

Hadoop4

2）在namenode的hdfs-site.xml配置文件中增加dfs.hosts.exclude属性(hadoop1上)

<property>
<name>dfs.hosts.exclude</name>
      <value>/opt/module/hadoop-2.7.2/etc/hadoop/dfs.hosts.exclude</value>
</property>

3）刷新namenode、刷新resourcemanager

[atguigu@hadoop1 hadoop-2.7.2]$ hdfs dfsadmin -refreshNodes

Refresh nodes successful

[atguigu@hadoop1 hadoop-2.7.2]$ yarn rmadmin -refreshNodes

17/06/24 14:55:56 INFO client.RMProxy: Connecting to ResourceManager at hadoop103/192.168.1.103:8033

4）检查web浏览器，退役节点的状态为decommission in progress（退役中），说明数据节点正在复制块到其他节点。

5）等待退役节点状态为decommissioned（所有块已经复制完成），停止该节点及节点资源管理器。注意：如果副本数是3，服役的节点小于等于3，是不能退役成功的，需要修改副本数后才能退役。

[atguigu@hadoop4 hadoop-2.7.2]$ sbin/hadoop-daemon.sh stop datanode
stopping datanode
[atguigu@hadoop4 hadoop-2.7.2]$ sbin/yarn-daemon.sh stop nodemanager
stopping nodemanager

6）从include文件中删除退役节点，再运行刷新节点的命令

​ （1）从namenode的dfs.hosts文件中删除退役节点hadoop105

hadoop1

hadoop2

hadoop3

​ （2）刷新namenode，刷新resourcemanager

[atguigu@hadoop1 hadoop-2.7.2]$ hdfs dfsadmin -refreshNodes

Refresh nodes successful

[atguigu@hadoop1 hadoop-2.7.2]$ yarn rmadmin -refreshNodes

17/06/24 14:55:56 INFO client.RMProxy: Connecting to ResourceManager at hadoop103/192.168.1.103:8033

7）从namenode的slave文件中删除退役节点hadoop4

hadoop1

hadoop2

hadoop3

8）如果数据不均衡，可以用命令实现集群的再平衡

[atguigu@hadoop1 hadoop-2.7.2]$ sbin/start-balancer.sh 

starting balancer, logging to /opt/module/hadoop-2.7.2/logs/hadoop-atguigu-balancer-hadoop102.out

Time Stamp               Iteration#  Bytes Already Moved  Bytes Left To Move  Bytes Being Moved