Linux SSH免密登入以及配置脚本

目录

一、ssh原理简单介绍

二、ssh免密登入实现步骤详解

三、ssh免密登入脚本实现

四、脚本实现免密登入多台设备

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一、ssh原理简单介绍

客户端生成一对公钥和私钥，并将自己的公钥发送到服务器上

其中公钥用来加密，私钥用来解密。

二、ssh免密登入实现步骤详解

我这就以服务器controller和客户端compute来做为例子

2.1、首先在controller上输入ssh-keygen -t rsa

一直敲回车就行，默认会在~/.ssh目录下生成密钥（id_rsa和id_rsa.pub），如果.ssh目录不存在,则会自动创建。

ssh-keygen -t rsa

[root@controller ~]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
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:
ff:98:6c:fd:f4:75:c9:a7:34:ea:97:56:7e:1d:f8:95 root@controller
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|                 |
|                 |
|                 |
|        S     . .|
|         .   ..E+|
|          ..  =*B|
|         ..+.++=B|
|         .+.++o o|
+-----------------+

其中第一个回车Enter file in which to save the key (/root/.ssh/id_rsa): 表示密钥存放的路径

第二个回车Enter passphrase (empty for no passphrase): 配置密码保护密钥，回车为不配置

第三个回车Enter same passphrase again: 确认第二步的密码

2.2、接下来便是要把公钥传到compute上面

这里用到了ssh-copy-id 命令，命令的作用是把本地主机的公钥复制到远程主机的authorized_keys文件上

命令格式为：ssh-copy-id root@compute_ip

ssh-copy-id [email protected]

[root@compute ~]# ssh-copy-id [email protected]
The authenticity of host '10.0.0.31 (10.0.0.31)' can't be established.
ECDSA key fingerprint is df:b0:ea:90:20:ea:fc:5d:cc:cf:94:63:59:6a:17:97.
Are you sure you want to continue connecting (yes/no)? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
[email protected]'s password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.

第一次连接会提示是否要继续连接

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

输入yes即可

[email protected]'s password: 

接着便是输入root用户的密码

查看compute节点上是否生成了authorized_keys

[root@compute ~]# ls .ssh
authorized_keys

2.3这样就完成了单方向的免密登入（controller登入compute），双向即在另一台节点上执行同样的操作就行了。

[root@controller .ssh]# ssh [email protected]
Last login: Sun Mar 13 21:34:18 2022 from 10.0.0.11
[root@compute ~]# 

三、ssh免密登入脚本实现

#!/bin/bash
#---------------设置ssh免密登入---------------#
HOST_IP_NODE=10.0.0.31
HOST_PASS_NODE=0000
#安装expect软件包
yum install expect -y
expect << EOF
set timeout 5
spawn ssh-keygen -t rsa
expect "id_rsa):" 
send "\r" 
expect "passphrase):" 
send "\r"
expect "again:"
send "\r" 
expect eof
EOF
expect << EOF
set timeout 5
spawn ssh-copy-id root@$HOST_IP_NODE
expect "(yes/no)?" 
send "yes\r"
expect "password:" 
send "$HOST_PASS_NODE\r" 
expect eof
EOF

四、脚本实现免密登入多台设备

#!/bin/bash
#---------------设置ssh免密登入对台设备---------------#
#设置要登入的节点ip地址
HOST_IP_NODE=(ip1 ip2 ip3 ... ipn)
HOST_PASS_NODE=(ps1 ps2 ps3 ... psn)
#安装expect软件包
yum install expect -y
expect << EOF
set timeout 5
spawn ssh-keygen -t rsa
expect "id_rsa):" 
send "\r" 
expect "passphrase):" 
send "\r"
expect "again:"
send "\r" 
expect eof
EOF

copy-id(){
expect << EOF
set timeout 5
spawn ssh-copy-id root@$1
expect "(yes/no)?" 
send "yes\r"
expect "password:" 
send "$2\r" 
expect eof
EOF
}

#循环遍历
num=${#HOST_IP_NODE[*]}
fun(){
    for i in 0 1 ... $num
      do
        copy-id root@${HOST_IP_NODE[i]} ${HOST_PASS_NODE[i]}
      done
}
fun