Hadoop启动namenode失败，端口号冲突问题解决

部署完Hadoop集群后，启动hadoop集群，有可能会遇到端口号冲突的问题

ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: Failed to start namenode.
java.net.BindException: Problem binding to [logsrv03:9000] java.net.BindException: 地址已在使用; For more details see:  http://wiki.apache.org/hadoop/BindException
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
	at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:792)
	at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:721)
	at org.apache.hadoop.ipc.Server.bind(Server.java:425)
	at org.apache.hadoop.ipc.Server$Listener.(Server.java:574)
	at org.apache.hadoop.ipc.Server.(Server.java:2215)
	at org.apache.hadoop.ipc.RPC$Server.(RPC.java:938)
	at org.apache.hadoop.ipc.ProtobufRpcEngine$Server.(ProtobufRpcEngine.java:534)
	at org.apache.hadoop.ipc.ProtobufRpcEngine.getServer(ProtobufRpcEngine.java:509)
	at org.apache.hadoop.ipc.RPC$Builder.build(RPC.java:783)
	at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.(NameNodeRpcServer.java:344)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createRpcServer(NameNode.java:673)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.initialize(NameNode.java:646)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:811)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.(NameNode.java:795)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.createNameNode(NameNode.java:1488)
	at org.apache.hadoop.hdfs.server.namenode.NameNode.main(NameNode.java:1554)
Caused by: java.net.BindException: 地址已在使用
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:444)
	at sun.nio.ch.Net.bind(Net.java:436)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.apache.hadoop.ipc.Server.bind(Server.java:408)
	... 13 more

出现原因：启动hdfs的时候端口号9000被另外一个程序占用了，出现端口冲突

解决办法：

1、查找这个端口号占用的程序，然后kill掉，重新启动hadoop

netstat -nltp | grep 端口号

2、在hadoop中配置core-site.xml，改变配置的端口号，重新启动