1、格式化

[root@master sbin]# hdfs namenode -format

2、命令hdfs dfsadmin

• 查看(hdfs dfsadmin -report)

[root@master ~]# hdfs dfsadmin -report

• 安全模式

#获取安全模式状态[root@master ~]# hdfs dfsadmin -safemode get#进入安全状态[root@master ~]# hdfs dfsadmin -safemode enter#离开安全模式[root@master ~]# hdfs dfsadmin -safemode leave

• 刷新节点

[root@master ~]# hdfs dfsadmin -refreshNodesRefresh nodes successful

• 打印网络拓扑

[root@master ~]# hdfs dfsadmin -printTopologyRack: /default-rack   192.168.30.11:50010 (slave1)   192.168.30.12:50010 (slave2)   192.168.30.13:50010 (slave3)

5、命令 hdfs fsck

• 查看坏块

[root@node1 ~]# hdfs fsck -list-corruptfileblocksConnecting to namenode via http://node1:50070The filesystem under path '/' has 0 CORRUPT files[root@node1 ~]# hdfs fsck -locationsConnecting to namenode via http://node1:50070FSCK started by root (auth:SIMPLE) from /192.168.30.11 for path / at Thu Jan 30 22:38:10 CST 2020.Status: HEALTHY Total size:1414 B Total dirs:3 Total files:1 Total symlinks:0 Total blocks (validated):1 (avg. block size 1414 B) Minimally replicated blocks:1 (100.0 %) Over-replicated blocks:0 (0.0 %) Under-replicated blocks:0 (0.0 %) Mis-replicated blocks:0 (0.0 %) Default replication factor:3 Average block replication:3.0 Corrupt blocks:0 Missing replicas:0 (0.0 %) Number of data-nodes:3 Number of racks:1FSCK ended at Thu Jan 30 22:38:10 CST 2020 in 1 millisecondsThe filesystem under path '/' is HEALTHY

• 删除坏块

[root@node1 ~]# hdfs fsck -delete

6、命令hdfs balancer

• 设置平衡阀

[root@node1 ~]# hdfs balancer -threshold 10

7、配置机架感知

• 修改core-site.xml文件

topology.script.file.name/opt/hadoop/etc/hadoop/topology.py

• 创建对应文件

[root@node1 current]# vi /opt/hadoop/etc/hadoop/topology.py#添加如下代码：#!/usr/bin/python#coding=utf-8import sysrack={"192.168.30.12":"/dc1/rack1",          "192.168.30.13":"/dc1/rack1",          "192.168.30.14":"/dc1/rack2",          "node2":"/dc1/rack1",          "node3":"/dc1/rack1",         "node4":"/dc1/rack2"        }if __name__=="__main__":   print rack.get(sys.argv[1],"/default-rack")

• 添加执行权限

[root@node1 current]#chmod u+x topology.py