簡單小述：
先登入跳板機，再通過跳板機登入到應用伺服器，可以保證業務伺服器的安全；業務伺服器不允許直接連線；通過允許從跳板機連線，業務伺服器不允許root使用者直接登陸。

實現原理

指令碼流程

• 列印選單->讀入->模式匹配

指令碼內容

#!/usr/bin/bash
#jumpserver
trap " " HUP INT OUIT TSIP
web1=192.168.146.130
web2=
mysql=
clear
while :
do
        cat <<-EOF
        ********************
        *     jumpserver   *
        *     1.web1       *
        *     2.web2       *
        *     3.mysql      *
        ********************
        EOF
        read -p "Please input number: " num
        #echo -en "\e[1;32 Please input number: \e[0m"
        #read num
        case "$num" in
        1)  ssh 
 
[email protected]$web1
                        ;;
        2)  ssh [email protected]$web2
                        ;;
        3)  ssh [email protected]$mysql
                        ;;
        q)  quit
            ;;
        "") ;;
        *)  echo "error"
        esac
done

然後進行金鑰認證

[[email protected]
 
 ~]# ssh-keygen    //建立金鑰
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
/root/.ssh/id_rsa already exists.
Overwrite (y/n)? 
[1]+  Terminated              ./jumpserver.sh
[[email protected] ~]# 
[[email protected] ~]# ssh-copy-id [email protected]    // 推送金鑰
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/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.

[[email protected] ~]# ssh [email protected]    //連線成功
Last failed login: Sun Nov 25 10:22:24 CST 2018 from 192.168.146.128 on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Sun Nov 25 10:13:22 2018
[[email protected] ~]$ exit
logout
Connection to 192.168.146.130 closed.
//推送成功之後就可以執行指令碼檔案
[[email protected] ~]# ./jumpserver.sh
********************
*     jumpserver   *
*     1.web1       *
*     2.web2       *
*     3.mysql      *
********************
Please input number: 1
Last login: Sun Nov 25 10:34:07 2018 from 192.168.146.128
[[email protected] ~]$ 
[[email protected] ~]$ exit
logout
Connection to 192.168.146.130 closed.
********************
*     jumpserver   *
*     1.web1       *
*     2.web2       *
*     3.mysql      *
********************
Please input number:    //執行成功