版本：Ubuntu 14.04.2 LTS (GNU/Linux 3.16.0-30-generic x86_64) SSH无密码登陆配置

1。在用户主目录下mkdir .ssh

因为/etc/ssh/sshd_config中 AuthorizedKeysFile默认值是”.ssh/authorized_keys”。

AuthorizedKeysFile存放该用户可以用来登录的 RSA/DSA 公钥。

该指令中可以使用下列根据连接时的实际情况进行展开的符号：

%% 表示’%’、%h 表示用户的主目录、%u 表示该用户的用户名。

经过扩展之后的值必须要么是绝对路径，要么是相对于用户主目录的相对路径。

默认值是”.ssh/authorized_keys”。

2。在.ssh目录下执行ssh-keygen -t rsa

ubuntu1@master:~/.ssh$ ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/home/ubuntu1/.ssh/id_rsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/ubuntu1/.ssh/id_rsa.

Your public key has been saved in /home/ubuntu1/.ssh/id_rsa.pub.

The key fingerprint is:

a6:15:be:f5:cd:45:f6:7b:80:18:47:37:6e:da:e2:d4 ubuntu1@master

The key’s randomart image is:

+–[ RSA 2048]—-+

| . o |

| . o . |

| … o o|

| . . + * o.|

| S o = E o|

| + o + + o.|

| . . o o..|

| .|

| |

+—————–+

ubuntu1@master:~/.ssh$ ll

total 16

drwxrwxr-x 2 ubuntu1 ubuntu1 4096 Jan 30 13:58 ./

drwxr-xr-x 17 ubuntu1 ubuntu1 4096 Jan 30 13:57 ../

-rw——- 1 ubuntu1 ubuntu1 1679 Jan 30 13:58 id_rsa

-rw-r–r– 1 ubuntu1 ubuntu1 396 Jan 30 13:58 id_rsa.pub

3。执行命令cat id_rsa.pub >> authorized_keys

将公钥信息保存到authorized_keys中

ubuntu1@master:~/.ssh$ chmod 644 authorized_keys

4。完成ssh无密码登陆配置

ubuntu1@master:~/.ssh$ ssh localhost

The authenticity of host ‘localhost (127.0.0.1)’ can’t be established.

ECDSA key fingerprint is b8:f0:bc:fb:79:1a:1e:d4:6b:6e:dd:75.

Are you sure you want to continue connecting (yes/no)? yes

Warning: Permanently added ‘localhost’ (ECDSA) to the list of known hosts.

Welcome to Ubuntu 14.04.2 LTS (GNU/Linux 3.16.0-30-generic x86_64)

Documentation: https://help.ubuntu.com/

Last login: Sat Jan 30 13:54:04 2016 from localhost