1、服务器上~/.ssh权限一定要正确：

# paste these into an SSH session that server (probably from

# another user account or root)

# change this to YOUR username on the server.

UN=example

# paste these lines verbatim:

sudo chown $UN:$UN /home/$UN/{.,.ssh/,.ssh/authorized_keys}

sudo chmod u+rwX,go-rwX,-t /home/$UN/{.ssh/,.ssh/authorized_keys}

sudo chmod go-w /home/$UN/

2、客户机的私钥权限也要正确:

报错：It is required that your private key files are NOT accessible by others.

修改权限：

chmod 600 ~/.ssh/id_rsa