Hadoop Datanode cannot connect Namenode

start-dfs.sh
The process is started successfully
Master:
65456 Jps
64881 NameNode
65057 DataNode

7380 NodeManager

65276 Secondarynamenode
Slave:
3607 DataNode

7380 NodeManager
3675 Jps

under Hadoop:
Slaves File Settings:
Master
slave1
Slave2
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Netstat-anp|grep 9000
TCP 0 0 192.168.1.200:9000 0.0.0.0:* LISTEN 64881/java
TCP 0 0 192.168.1.200:9000 192.168.1.200:42846 established 64881/java
TCP 0 0 192.168.1.200:42853 192.168.1.200:9000 time_wait-
TCP 0 0 192.168.1.200:42846 192.168.1.200:9000 established 65057/java
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Problem Description:
under the HTTP://MASTER:50070/monitoring page.
Live Nodes is 1.
only master Datanode can see that the other two slave have processes but cannot connect to master.
and inThe current file is not generated under slave dfs/data
View logs as:

2016-11-08 13:12:31,099 INFO org.apache.hadoop.ipc.Client:Retrying connect to server:master/192.168.0.100:9000. Already tried 6 time (s); Retry policy is Retryuptomaximumcountwithfixedsleep (maxretries=10, sleeptime=1000 MILLISECONDS)

The reason is Centos7. Turn off SELinux and iptables. To turn off dynamic firewalls Shutting down the firewall: *********** is very important *********** # SYSTEMCTL Status Firewalld.service--View firewall status # Systemctl Stop Firewalld.service--shut down the firewall # systemctl Disable Firewalld.service--permanently shut down the firewall

Hadoop Datanode cannot connect Namenode