两台服务器实现免密登录
可以用于配置多台（>2）服务器之间的免密登录
使用shell的远程操作命令ssh，通过ssh协议，连接192.168.100.148服务器，执行echo 1命令。
ssh 192.168.100.148 'echo 1'
输出如下：
[root@hadoop001 ~]# ssh 192.168.100.148 'echo 1'
[email protected]'s password:
1
需要输入192.168.100.148的登录密码
现在实现免密登录
目标：231访问248不需要输入密码
1、231生成密钥对
# cd /root/.ssh (如果没有.ssh, 请在root目录下mkdir .ssh chmod 755 .ssh)
# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): （直接回车）
Enter passphrase (empty for no passphrase): （直接回车）
Enter same passphrase again: （直接回车）
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:06:96:6b:56:0c:33:a4:24:16:8c:06:35:9b:98:8b:e7 [email protected]
2、将生成的公钥id_rsa.pub复制到148机器上
ssh-copy-id -i root/.ssh/id_rsa.pub [email protected]
说明：将231上生成的公钥文件id_rsa.pub复制到148的/root/.ssh/authorized_keys里，ssh-copy-id -i表示追加写的方式添加到authorized_keys。可以实现多个机器访问148.
[root@hadoop001 .ssh]# ssh-copy-id -i /root/.ssh/id_rsa.pub [email protected]
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
[email protected]'s password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.
3、验证
[root@hadoop001 .ssh]# ssh [email protected] 'echo 1'
1
不用输入密码，表示配置成功了。