SSH免密登陆

不念不忘少年蓝@ 2022-06-12 14:12 350阅读 0赞

# SSH免密登陆 #

现在很多部署在Linux集群的软件系统都会涉及到ssh免密登陆，例如Oracle的Rac、Hadoop等，下面将简单介绍一下SSH的免密登陆  
前期准备：VirtualBox软件，Ubuntu虚拟机2台（node,node1）  
node:192.168.57.101  
node1:192.168.57.103  
现在想实现两个节点之间彼此的免密ssh登陆

### 生成rsa密钥 ###

> root@node:~\# ssh-keygen -t rsa -P ”

参数P表示存在密码，可以在后面加自定义密码，我这里为了方便用的是-P ”空字符串表示密码为空，当然也可以不加P参数但是需要多回车两次，回车后就会在/root目录下生成ssh目录，如果你用的其他用户登陆如XX则会在/home/XX下生成.ssh目录，目录里有id\_rsa和id\_rsa.pub文件，这两个文件就是用来实现免密登陆的。

root@node:~# ssh-keygen -t rsa -P ''
    Generating public/private rsa key pair.
    Enter file in which to save the key (/root/.ssh/id_rsa): 
    Created directory '/root/.ssh'.
    Your identification has been saved in /root/.ssh/id_rsa.
    Your public key has been saved in /root/.ssh/id_rsa.pub.
    The key fingerprint is:
    SHA256:jxfmhN3Oofu0DzIbGv3mGBw6VgcX5YBnkp1XemeiqfY root@node
    The key's randomart image is:
    +---[RSA 2048]----+
    |           +oo...|
    |          + =+.. |
    |          .+..+ +|
    |         o + o +.|
    |        S B *    |
    |         @ O .   |
    |        * # = |
    |       . * %.o   |
    |        . ++E..  |
    +----[SHA256]-----+

### 复制密钥 ###

使用scp命令将生成的id\_rsa.pub文件上传到node1指定目录

> root@node:~\# scp /root/.ssh/id\_rsa.pub root@192.168.57.103:/root

由于目前没有实现免密登陆所以需要输入密码

The authenticity of host '192.168.57.103 (192.168.57.103)' can't be established.
    ECDSA key fingerprint is SHA256:+rYv2fdh3HngKOh1p/X1LTRHn66BW9jA8EPJO6vwiN8.
    Are you sure you want to continue connecting (yes/no)? yes
    Warning: Permanently added '192.168.57.103' (ECDSA) to the list of known hosts.
    root@192.168.57.103's password: 
    id_rsa.pub                                       100%  391     0.4KB/s   00:00

### 添加authorzied\_keys ###

下一步将在node1把从node复制过来的id\_rsa.pub文件添加到.ssh/authorzied\_keys文件中  
在node1端

> root@node1:~\# cat id\_rsa.pub >> .ssh/authorized\_keys

然后再给authorized\_keys添加600的权限

> root@node1:~\# chmod 600 .ssh/authorized\_keys

至此完成了ssh免密登陆的配置，测试一下成功，同理从node1免密登陆也是一样的

root@node:~# ssh 192.168.57.103
    Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-62-generic x86_64)
    
     * Documentation:  https://help.ubuntu.com
     * Management:     https://landscape.canonical.com
     * Support:        https://ubuntu.com/advantage
    
    8 个可升级软件包。
    8 个安全更新。
    
    
    Last login: Thu Jul  6 15:32:09 2017 from 192.168.57.1