linux管理机的无密码登录

1.生成公私钥对（Generating public/private rsa key pair）：

# ssh-keygen

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa):

一路回车，生成完毕，生成之后的默认存放路经：

privatekey:  ~/.ssh/id_rsa

publickey:  ~/.ssh/id_rsa.pub

2.在服务器上部署publickey:

cd ~/.ssh/

cat id_rsa.pub >> authorized_keys

ssh登录进来后自读~/.ssh/authorized_keys

3.由私钥生成公钥（export public key from private key）:

ssh-keygen -y -f PrivateKeyFile

4.普通用户部署：

如果是root用户，默认在/root/下有.ssh,并且是700权限，普通用户家目录下没有.ssh

mkdir ~/.ssh

chmod 700 ~/.ssh

cat id_rsa.pub >> authorized_keys