当我运行start dfs时，出现以下错误，看起来我需要告诉hadoop使用不同的端口，因为这是我在ssh到localhost时所需要的。换言之，以下工作成功： ssh -p 2020 localhost. ```
[Wed Jan 06 16:57:34 root@~]# start-dfs.sh
16/01/06 16:57:53 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [localhost]
localhost: namenode running as process 85236. Stop it first.
localhost: datanode running as process 85397. Stop it first.
Starting secondary namenodes [0.0.0.0]
0.0.0.0: ssh: connect to host 0.0.0.0 port 22: Connection refused
16/01/06 16:57:56 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable

core-site.xml：

<property>
    <name>dfs.namenode.name.dir</name>
    <value>file:///hadoop/hdfs/namenode</value>
</property>

<property>
    <name>dfs.datanode.data.dir</name>
    <value>file:///hadoop/hdfs/datanode</value>
</property>