linux ssh免密码访问

有一个master机器经常向slave机器发送文件和执行命令，免密码配置可以省去输入密码的麻烦。

 

master配置
ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
chmod 644 ~/.ssh/authorized_keys
ssh localhost # 测试是否可以免密码访问本机

#ssh客户端免yes/no输入
vi /etc/ssh/ssh_config
> StrictHostKeyChecking no

slave配置
ssh-keygen -t rsa -P '' -f ~/.ssh/id_rsa

master分发公钥
scp ~/.ssh/id_rsa.pub [email protected]:~/.ssh/id_rsa.pub

slave授权
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
chmod 644 ~/.ssh/authorized_keys

=============

错误诊断：

Q：配置都OK的，但master访问slave还是需要密码

扫描二维码关注公众号，回复： 1334112 查看本文章

A：这个通常是目录权限的问题，如/root/.ssh权限要求是700，/root权限也要是700，诊断方法：slave机器执行：tail  /var/log/secure -f，然后mster执行连接命令，会有如下提示：

Sep 3 16:34:30 localhost sshd[17960]: Authentication refused: bad ownership or modes for directory /root/.ssh
Sep 3 16:34:30 localhost sshd[17960]: Authentication refused: bad ownership or modes for directory /root/.ssh
Sep 3 16:34:48 localhost sshd[17961]: Connection closed by 172.16.11.189
Sep 3 16:34:49 localhost sshd[17963]: Authentication refused: bad ownership or modes for directory /root
Sep 3 16:34:49 localhost sshd[17963]: Authentication refused: bad ownership or modes for directory /root

可见： /root/.ssh 和/root两个目录权限有问题，改为700就OK了。