hadoop 动态增加节点

前面写过一篇 hadoop集群安装配置 的文章。只用了二台机器，假如机器快满了，就需要在加机器。hadoop加节点，不需要重启hadoop服务。

一，增加节点的准备工作

1，修改主机名，所有节点机器hosts保持一至

2，ssh免密码登录

3，修改slaves，所有节点一样

scp把老节点的etc/hadoop的配置copy到新的节点

二，在新节点的启动

[root@bigserver3 hadoop]# ./sbin/hadoop-daemon.sh start datanode
[root@bigserver3 hadoop]# ./sbin/yarn-daemon.sh start nodemanager

[root@bigserver3 hadoop]# jps
1569 Jps
1401 DataNode
1499 NodeManager

[root@bigserver3 hadoop]# yarn node -list
18/12/27 22:35:41 INFO client.RMProxy: Connecting to ResourceManager at bigserver1/10.0.0.237:8032
Total Nodes:2
 Node-Id Node-State Node-Http-Address Number-of-Running-Containers
bigserver3:40901 RUNNING bigserver3:8042 0
bigserver2:43959 RUNNING bigserver2:8042 0

三，均衡hdfs存储

1，设置环境变量

# echo "export PATH=/bigdata/hadoop/bin:$PATH" >> ~/.bashrc
# source ~/.bashrc

这样就可以直接使用hadoop/bin目录下的命令了

2，配置均衡带宽，默认是1M

# hdfs dfsadmin -setBalancerBandwidth 52428800 //设置50M
Balancer bandwidth is set to 52428800

3，均衡hdfs的存储

[root@bigserver3 hadoop]# ./sbin/start-balancer.sh -threshold 5
starting balancer, logging to /home/bigdata/hadoop/logs/hadoop-root-balancer-bigserver3.out

默认是10，数字越大均衡时间越短，越不均衡，数字越小均衡时间越长，越均衡

4，查看一下均衡后的结果

[root@bigserver3 hadoop]# hadoop dfsadmin -report
DEPRECATED: Use of this script to execute hdfs command is deprecated.
Instead use the hdfs command for it.

Configured Capacity: 2382153052160 (2.17 TB)
Present Capacity: 2381362919833 (2.17 TB)
DFS Remaining: 2381087567872 (2.17 TB)
DFS Used: 275351961 (262.60 MB)
DFS Used%: 0.01%
Under replicated blocks: 20
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0

-------------------------------------------------
Live datanodes (2):

Name: 10.0.0.193:50010 (bigserver3)
Hostname: bigserver3
Decommission Status : Normal
Configured Capacity: 441499058176 (411.18 GB)
DFS Used: 3000729 (2.86 MB)
Non DFS Used: 392808039 (374.61 MB)
DFS Remaining: 441103249408 (410.81 GB)
DFS Used%: 0.00% //是否均衡主要看这二项
DFS Remaining%: 99.91% //是否均衡主要看这二项
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 Dec 27 22:38:51 EST 2018

Name: 10.0.0.236:50010 (bigserver2)
Hostname: bigserver2
Decommission Status : Normal
Configured Capacity: 1940653993984 (1.77 TB)
DFS Used: 272351232 (259.73 MB)
Non DFS Used: 397324288 (378.92 MB)
DFS Remaining: 1939984318464 (1.76 TB)
DFS Used%: 0.01% //是否均衡主要看这二项
DFS Remaining%: 99.97% //是否均衡主要看这二项
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 Dec 27 22:38:51 EST 2018

四，在master测试关闭和启动hadoop集群

[root@bigserver1 sbing]# ./stop-all.sh
This script is Deprecated. Instead use stop-dfs.sh and stop-yarn.sh
Stopping namenodes on [bigserver1]
bigserver1: stopping namenode
bigserver2: stopping datanode
bigserver3: stopping datanode
Stopping secondary namenodes [0.0.0.0]
0.0.0.0: stopping secondarynamenode
stopping yarn daemons
stopping resourcemanager
bigserver2: stopping nodemanager
bigserver3: stopping nodemanager
no proxyserver to stop

[root@bigserver1 sbing]# ./start-all.sh
This script is Deprecated. Instead use start-dfs.sh and start-yarn.sh
Starting namenodes on [bigserver1]
bigserver1: starting namenode, logging to /home/bigdata/hadoop/logs/hadoop-root-namenode-bigserver1.out
bigserver2: starting datanode, logging to /home/bigdata/hadoop/logs/hadoop-root-datanode-bigserver2.out
bigserver3: starting datanode, logging to /home/bigdata/hadoop/logs/hadoop-root-datanode-bigserver3.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /home/bigdata/hadoop/logs/hadoop-root-secondarynamenode-bigserver1.out
starting yarn daemons
starting resourcemanager, logging to /home/bigdata/hadoop/logs/yarn-root-resourcemanager-bigserver1.out
bigserver2: starting nodemanager, logging to /home/bigdata/hadoop/logs/yarn-root-nodemanager-bigserver2.out
bigserver3: starting nodemanager, logging to /home/bigdata/hadoop/logs/yarn-root-nodemanager-bigserver3.out

这一步对于新增节点来说，是不需要的。只是个人测试。