ssh 无密码互通

节点n1 n2 n3 互通

第一步：n1->n2互通

　　admin@n1 > ssh-keygen -d

　　

　　 admin@n1 > scp id_dsa.pub n2:~/.ssh/authorized_keys

　　这样就实现了 ssh n2 无密码登录

下面的同理：将本机生成的.pub文件追加到对方的authorized_keys文件里面就可以了。

这里出现过一个问题。n1->n2 正常，n2->n1同样的步骤就是不行，admin@n2 > ssh n1 总是需要密码。怎么回事？时间的问题？修改时间同样不行。

最后找出是 .ssh 权限的问题。

Make sure the permissions on the ~/.ssh directory and its contents are proper. When I first set up my ssh key auth, I didn't have the ~/.ssh folder properly set up, and it yelled at me.

• Your home directory ~ and your ~/.ssh directory on the remote machine must be writable only by you: rwx------ and rwxr-xr-x are fine, but rwxrwx--- is no good, even if you are the only user in your group (if you prefer numeric modes: 700 or 755, not 775).
• Your private key file (on the local machine) must be readable and writable only by you: rw-------, i.e. 600.
• Your ~/.ssh/authorized_keys file (on the remote machine) must be readable (at least 400), but you'll need it to be also writable (600) if you will add any more keys to it.
• Also, if SELinux is set to enforcing, you may need to run restorecon -R -v ~/.ssh (see e.g. Ubuntu bug 965663 and Debian bug #658675; this is patched in CentOS 6).