两台linux服务器之间建立ssh信任关系
http://bbs.linuxtone.org/thread-2010-1-1.html

前景:
昨天在家配置rsync同步用到命令：
#rsync -avz --progress -e "ssh -p22" root@192.168.22.149:/data/www/wwwroot/ /data/www/wwwroot/
复制代码
提示我输入192.168.22.149这台机器的密码
可是这在实际环境中运用是不可取的，要让B与A时建立ssh信任，登陆不要输入密码

过程：
软硬件环境： 两台linux服务器A和B 都编译安装上最新版的openSSH(建议)

openSSH的默认设置是允许root可以直接login. (PermitRootLogin yes),暂且保留这种设置，我们先考虑如何用SSH直接从A到B不需要密码，假设用用户root登录到A，想SSH到B也作为root不需要密码。

1。 分别从A和B上登录作为root后运行
#ssh-keygen
目的是简单地在/root下创建目录.ssh,当提示输入 passphase时打入两次回车。这将生成下面这两个文件：
/root/.ssh/id_rsa
/root/.ssh/id_rsa.pub
复制代码
2。 先测试一下，从A登录作为root，输入
#ssh B
会要求提示
root@192.168.22.149's password: 
复制代码
3。 现在从A登录作为root，运行
#scp /root/.ssh/id_rsa.pub root@[B:ip]:/root/.ssh/authorized_keys
文件名必须不能弄错。

4。现在再从A运行
#ssh B
//则不需要密码了

实例：
A:
#ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):  [回车]
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): [回车]
Enter same passphrase again: [回车]
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:
01:90:08:9e:7d:42:69:01:96:52:d7:ca:9f:53:43:df root@test-1
复制代码
B：
#ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): [回车]
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): [回车]
Enter same passphrase again: [回车]
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:
3c:40:6d:c7:24:d1:99:27:5f:ea:5e:a4:41:0d:5a:26 root@test-2
复制代码
#scp /root/.ssh/id_rsa.pub root@192.168.22.149:/root/.ssh/authorized_keys
root@192.168.22.149's password: [输入密码]
复制代码
# ssh 192.168.22.149
Last login: Mon Mar  2 11:37:22 2009 from 192.168.22.156
复制代码
信任关系建立成功……