范例17_6：：开发企业级Shell跳板机案例。要求用户登录到跳板机仅能执行管理员给定的选项动作，不允许以任何形式中断脚本到跳板机服务器上执行任何系统命令。
方法1：
1）首先做好SSH密钥验证（跳板机地址192.168.33.128）。
以下操作命令在所有机器上操作：
[[email protected] ~]# useradd jump #<==要在所有机器上操作。
[[email protected] ~]# echo 123456|passwd --stdin jump #<==要在所有机器上操作。
Changing password for user jump.
passwd: all authentication tokens updated successfully.
以下操作命令仅在跳板机上操作：
[[email protected] ~]# su - jump
[[email protected] ~]$ ssh-keygen -t dsa -P ‘‘ -f ~/.ssh/id_dsa >/dev/null 2>&1 #<==生成密钥对。
[[email protected] ~]$ ssh-copy-id -i ~/.ssh/id_dsa.pub 192.168.33.130 #<==将公钥分发到其他服务器。
The authenticity of host ‘192.168.33.130 (192.168.33.130)‘ can‘t be established.
RSA key fingerprint is fd:2c:0b:81:b0:95:c3:33:c1:45:6a:1c:16:2f:b3:9a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.33.130‘ (RSA) to the list of known hosts.
[email protected]‘s password:
Now try logging into the machine, with "ssh ‘192.168.33.130‘", and check in:
.ssh/authorized_keys
to make sure we haven‘t added extra keys that you weren‘t expecting.
[[email protected] ~]$ ssh-copy-id -i ~/.ssh/id_dsa.pub 192.168.33.129 #<==将公钥分发到其他服务器。
The authenticity of host ‘192.168.33.129 (192.168.33.129)‘ can‘t be established.
RSA key fingerprint is fd:2c:0b:81:b0:95:c3:33:c1:45:6a:1c:16:2f:b3:9a.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘192.168.33.129‘ (RSA) to the list of known hosts.
[email protected]‘s password:
Now try logging into the machine, with "ssh ‘192.168.33.129‘", and check in:
.ssh/authorized_keys
to make sure we haven‘t added extra keys that you weren‘t expecting.
2）实现传统的远程连接菜单选择脚本。
菜单脚本如下：
cat <<menu
1)oldboy-192.168.33.129
2)oldgirl-192.168.33.130
3)exit
menu
3）利用linux信号防止用户中断信号在跳板机上操作。
function trapper () {
trap ‘:‘ INT EXIT TSTP TERM HUP #<==屏蔽这些信号。
}
4）用户登录跳板机后即调用脚本（不能命令行管理跳板机），并只能按管理员的要求选单。
以下为实战内容。
脚本放在跳板机上：
[[email protected] ~]# echo ‘[ $UID -ne 0 ] && . /server/scripts/jump.sh‘ >/etc/profile.d/jump.sh
[[email protected] ~]# cat /etc/profile.d/jump.sh
[ $UID -ne 0 ] && . /server/scripts/jump.sh
[[email protected] scripts]# cat /server/scripts/jump.sh
#!/bin/sh
#oldboy training
trapper() {
trap ‘:‘ INT EXIT TSTP TERM HUP #<==定义需要屏蔽的信号，冒号表示啥都不做。
}
main(){
while :
do
trapper
clear
cat <<menu
1)Web01-192.168.33.129
2)Web02-192.168.33.130
menu
read -p "Pls input a num.:" num
case "$num" in
1)
echo ‘login in 192.168.33.129.‘
ssh 192.168.33.129
;;
2)
echo ‘login in 192.168.33.130.‘
ssh 192.168.33.130
;;
110)
read -p "your birthday:" char
if [ "$char" = "0926" ];then
exit
sleep 3
fi
;;
*)
echo "select error."
esac
done
}
main
执行效果如下：
[[email protected] ~]# su - jump #<==切到普通用户即弹出菜单，工作中直接用jump登录，即弹出菜单。
1)Web01-192.168.33.129
2)Web02-192.168.33.130
Pls input a num.:
1)Web01-192.168.33.129
2)Web02-192.168.33.130
Pls input a num.:1 #<==选1进入Web01服务器。
login in 192.168.33.129.
Last login: Tue Oct 11 17:23:52 2016 from 192.168.33.128
[[email protected] ~]$ #<==按ctrl+d退出到跳板机服务器再次弹出菜单。
1)Web01-192.168.33.129
2)Web02-192.168.33.130
Pls input a num.:2 #<==选2进入Web02服务器。
login in 192.168.33.130.
Last login: Wed Oct 12 23:30:14 2016 from 192.168.33.128
[[email protected] ~]$ #<==按ctrl+d退出到跳板机服务器再次弹出菜单。
1)Web01-192.168.33.129
2)Web02-192.168.33.130
Pls input a num.:110 #<==选110进入跳板机命令提示符。
your birthday:0926 #<==需要输入特别码才能进入的，这里管理员通道，密码要保密呦。
[[email protected] scripts]# #<==跳板机管理命令行。
本文内容来源于：《跟老男孩学linux运维：Shell高级编程实战》
老男孩教育官网：www.oldboyedu.com