ubuntu伪分布式的配置示例：
1.安装“ssh server”。
2.再安装“sun jdk6”，必须要java6及其以上版本。
3.生成SSH证书，配置SSH加密key，操作步骤：
www@ubuntu:~$ su – www
Password:
www@ubuntu:~$ ssh-keygen -t rsa -P ""
Generating public/private rsa key pair.
Enter file in which to save the key (/home/www/.ssh/id_rsa):
Your identification has been saved in /home/www/.ssh/id_rsa.
Your public key has been saved in /home/www/.ssh/id_rsa.pub.
The key fingerprint is:
a8:67:6f:bd:04:13:41:5f:a7:13:2d:84:e7:8a:8c:43 www@ubuntu
The key's randomart image is:
+–[ RSA 2048]—-+
| .o o+.. |
| o..o+. |
| . .oo. |
| E. . .. |
| ..oS. . |
| .o oo. |
| . o. .. |
| o …. |
| .. .. |
+—————–+
www@ubuntu:~$
www@ubuntu:~$ cat $HOME/.ssh/id_rsa.pub >> $HOME/.ssh/authorized_keys
www@ubuntu:~$
4.配置完成后，可以测试一下，例如：
www@ubuntu:~$ ssh localhost
The authenticity of host 'localhost (::1)' can't be established.
RSA key fingerprint is d7:87:25:47:ae:02:00:eb:1d:75:4f:bb:44:f9:36:26.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'localhost' (RSA) to the list of known hosts.
Linux ubuntu 2.6.32-22-generic #33-Ubuntu SMP Wed Apr 28 13:27:30 UTC 2010 i686 GNU/Linux
Ubuntu 10.04 LTS
[...snipp...]
www@ubuntu:~$