我跑不了 start-dfs.sh ```
ubuntu@UBUNTU:~$ start-dfs.sh
14/10/19 19:26:50 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [localhost]
localhost: ssh: connect to host localhost port 22: Connection refused
localhost: ssh: connect to host localhost port 22: Connection refused
Starting secondary namenodes [0.0.0.0]
0.0.0.0: ssh: connect to host 0.0.0.0 port 22: Connection refused
14/10/19 19:27:19 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
ubuntu@UBUNTU:~$

安装hadoop时，我执行了以下操作：

ssh-keygen -t rsa -P ''
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys