ssh(ssh-keygen)配置免输入密码登录远程主机的方法

环境：
本地主机：ha01
eth0: 192.168.1.100 //对外IP地址

远程主机：ha02
eth0: 192.168.1.200 //对外IP地址

本地主机ha01配置：

[root@ha01 /]# cd /etc/ssh
[root@ha01 ssh]# ssh-keygen -t rsa -N "" (该步骤生成key公私密钥对，-N ""表示密钥对短语为空)
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
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:
82:2c:74:43:8e:16:f4:ef:ac:91:0f:d7:6f:a6:f3:59 root@ha01

复制公共密钥到远程主机（原始方法）：
若ha02服务器上/root/.ssh/authorized_keys文件不存在

[root@ha01 ssh]# scp /root/.ssh/id_rsa.pub root@192.168.1.200:/root/.ssh/authorized_keys

若authorized_keys文件存在
ha01上执行：

[root@ha01 ssh]# scp /root/.ssh/id_rsa.pub root@192.168.1.200:/root/.ssh/

ha02上执行：

[root@ha02 /]# cat /root/.ssh/id_rsa.pub >> /root/.ssh/authorized_keys

复制公共密钥到远程主机（新方法）：
可以使用ssh-copy-id方便安全的将公共密钥复制到远程主机

ha01上执行：

[root@ha01 ssh]# ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.1.200

SSH登录测试：

[root@ha01 ssh]# ssh ha02
Last login: Fri Apr 8 10:41:28 2011 from ha01