ssh无密码登陆

服务器之间，可以互相之间用ssh直接可以登录，不需要输入密码：
A服务器地址：192.168.0.1
B服务器地址：192.168.0.2
在A上执行：
[root@localhost .ssh]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):   
Enter passphrase (empty for no passphrase):              
Enter same passphrase again:                                     
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
6a:83:7b:6a:52:60:33:de:e0:c1:55:52:2b:c7:59:c9 [e-mail]

[root@localhost .ssh]#cd /root/.ssh
[root@localhost .ssh]#cat id_rsa.pub >> authorized_keys
接下来，我们这个文件authorized_keys用scp命令复制到第二台机器的/root/.ssh/目录下
[root@localhost .ssh]#scp authorized_keys 192.168.0.2:/root/.ssh/
登陆B服务器，此时无需输入密码即可登陆：
[root@localhost .ssh]#ssh 192.168.0.2
Last login: Fri Dec 13 17:14:17 2013

如果不奏效的话，检查配置文件/etc/ssh/sshd_config
AuthorizedKeysFile      .ssh/authorized_keys
并去掉前面的注释，重启sshd服务即可