Linux密钥认证

网站集群批量管理-秘钥认证

一、概述

管理更加轻松：两个节点，通过秘钥形式进行访问，不需要输入密码，单向

应用场景：

一些服务在使用前要求做秘钥认证

手动写批量管理脚本

名字：秘钥认证，免密码登录，双机互信

二、原理

秘钥对：

公钥：public key 一般以.pub结尾

私钥：private key 没有特殊的结尾

[root@m01 ~]# ll .ssh
total 12
-rw------- 1 root root 1679 Feb  1 10:11 id_rsa        #私钥
-rw-r--r-- 1 root root  390 Feb  1 10:11 id_rsa.pub    #公钥
-rw-r--r-- 1 root root  686 Feb  1 11:11 known_hosts   #存放连接时是否需要输入yes or no

三、极速上手指南

角色	主机名	内网ip	公网ip
管理机	m01	172.16.1.61	10.0.0.61
被管理机	nfs	172.16.1.31	10.0.0.31
被管理机	web01	172.16.1.7	10.0.0.7
被管理机	backup	172.16.1.41	10.0.0.41

1.基本检查

#检查管理机与被管理机是否联通
#ping 
[root@m01 ~]# ping 172.16.1.7
PING 172.16.1.7 (172.16.1.7) 56(84) bytes of data.
64 bytes from 172.16.1.7: icmp_seq=1 ttl=64 time=0.300 ms
64 bytes from 172.16.1.7: icmp_seq=2 ttl=64 time=0.184 ms
^C
--- 172.16.1.7 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.184/0.242/0.300/0.058 ms
 
#22端口，sshd服务开启或客户访问
[root@m01 ~]# nmap -p22 172.16.1.31 172.16.1.7 172.16.1.41
 
Starting Nmap 6.40 ( http://nmap.org ) at 2023-02-01 15:14 CST
Nmap scan report for nfs01 (172.16.1.31)
Host is up (0.00015s latency).
PORT   STATE SERVICE
22/tcp open  ssh
MAC Address: 00:0C:29:87:19:20 (VMware)
 
Nmap scan report for web01 (172.16.1.7)
Host is up (0.00020s latency).
PORT   STATE SERVICE
22/tcp open  ssh
MAC Address: 00:0C:29:2A:09:7D (VMware)
 
Nmap scan report for backup (172.16.1.41)
Host is up (0.00018s latency).
PORT   STATE SERVICE
22/tcp open  ssh
MAC Address: 00:0C:29:DB:3F:AB (VMware)
 
Nmap done: 3 IP addresses (3 hosts up) scanned in 0.66 seconds

2.创建秘钥对

[root@m01 ~]# 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:
SHA256:qBDXHAdOru29Wu3F7A/EphYrA+xc3HMOtgsJJltoAB0 root@m01
The key's randomart image is:
+---[RSA 2048]----+
|..E.  +..        |
| ..  * o         |
|  o . =          |
|   + = o . .     |
|  . = O S * =    |
|   o X = + #     |
|    o + B * *    |
|       . B + .   |
|      ... o ...  |
+----[SHA256]-----+
 
#注意创建的时候，可以不加t
#-t 指定加密的类型
#默认通过rsa方法对数据进行加密
 

3.分发公钥

[root@m01 ~]# ssh-copy-id -i .ssh/id_rsa.pub 172.16.1.41
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: ".ssh/id_rsa.pub"
The authenticity of host '172.16.1.41 (172.16.1.41)' can't be established.
ECDSA key fingerprint is SHA256:fVjvhVF2qU+PCOqsrVTrbxa/aNB4dzNmGRJTw1iIZ1s.
ECDSA key fingerprint is MD5:0f:00:32:1c:41:31:af:a2:f5:e8:64:40:2c:cf:98:98.
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
root@172.16.1.41's password: 
 
Number of key(s) added: 1
 
Now try logging into the machine, with:   "ssh '172.16.1.41'"
and check to make sure that only the key(s) you wanted were added.

4.连接测试

[root@m01 ~]# ssh 172.16.1.41 hostname
backup

温馨提示：

ssh-copy-id 公钥被存放在对方服务器的用户家目录下面

名字变为了：authorized_keys

[root@backup ~]# ll .ssh
total 8
-rw------- 1 root root 390 Feb  1 15:16 authorized_keys

如果管理机的秘钥重新生成，又重新发送，那么authorized_keys中的秘钥就会变成2个

[root@nfs ~]# cat .ssh/authorized_keys 
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDEak/lEI0Aoy8MJhsYaALPAOCtmAV6l9YTZ/t9jJX+vMpC2EUuKzOuii0LwLgQ0ovqWAERJLaFpSlIHZg9jio7vLwsm8KiBtfiWVihG6NDkj8Y2LAUrNUbMFYHpO4z+jlJNbeo+0rJIAKsAoFPGMjYjmm2/oZZRz8YsHrpHsJpidXCW161v7Cn5tfJTOSEixeKoCbFKQBCcb36hHT9sqLFK9S2/PiPJZi4N8FiBcBxz4DIq9dIPgj6BCG99YqBIRtIg6dB1WdDsqKXrdDxDwmSYNWfxBKkII0DncxSM8cX8+YtAis5gRubxvsOGIpZ5LjKnpQgGWQUwNu0FaIe9AhT root@m01
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCvqqbNj++CGwQROG+1kKB6uxcK54le6Pz8K+SFoq5GKspmt2pjMupzsvM0okEMhJhMRH8e/tZlfMRNOa82mF3FkKhWCBAsK+YAY5oHUzEnS7M+7V6L6JSyi8No2RG/xxC51zWiJgExAFAXTrJCcmN8npeKyGwcBHaKpDtqb3sigm6mty05rQmjKd52BBjTbu19jen9D+FxhbJHHU00uBWq0b9XrpvTqN5mp1qbIreB/U5YZg1j4skEmqtG1WzjEe6Q/oxkQbBnubZ17C7kvTt9xSre6TnLaPPb2sFDCb/6V983wxCQrkuYjTcfRkgzPZtjN/xQk+lfmFiKTdZAU8dv root@m01

四、自动化创建与分发密钥

步骤：

1. 创建秘钥对
2. 分发公钥的时候：yes/no （yes后会把信息保存到.ssh/known_hosts）
3. 分发公钥的时候：输入密码

1.自动化创建密钥

[root@m01 ~]# ssh-keygen -f ~/.ssh/id_rsa -P ''
Generating public/private rsa key pair.
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:UebPlzDbK0NcyDAuNoDMR0aa5jUNcwx63bF5ftW/9R4 root@m01
The key's randomart image is:
+---[RSA 2048]----+
|   o +Oo. *      |
|    +=.B.* B .  .|
|    =.+ B * * . o|
|   o o o + * * o.|
|    .   S   B = o|
|           . o .+|
|            o .E.|
|             o ..|
|                .|
+----[SHA256]-----+
 
-f 用于指定私钥的位置
-P 密钥短语，设置为空。就是输完ssh-keygen，需要敲的两下回车
 

2.自动化分发公钥（解决yes/no问题）

第1次远程的提示 yes/no,主机密钥信息检查,输入yes后存放到~/.ssh/known_hosts

解决思路：临时取消即可，连接的时候不检查主机信息

-o StrictHostKeyChecking=no 临时不检查主机信息.

#不加-o参数时
[root@m01 ~]# ssh-copy-id -i .ssh/id_rsa.pub 10.0.0.31   
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: ".ssh/id_rsa.pub"
The authenticity of host '10.0.0.31 (10.0.0.31)' can't be established.
ECDSA key fingerprint is SHA256:fVjvhVF2qU+PCOqsrVTrbxa/aNB4dzNmGRJTw1iIZ1s.
ECDSA key fingerprint is MD5:0f:00:32:1c:41:31:af:a2:f5:e8:64:40:2c:cf:98:98.
Are you sure you want to continue connecting (yes/no)? ^C 
#加上-o参数时
[root@m01 ~]# ssh-copy-id -oStrictHostKeyChecking=no -i .ssh/id_rsa.pub 10.0.0.31
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: ".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
root@10.0.0.31's password: 
 
Number of key(s) added: 1
 
Now try logging into the machine, with:   "ssh -o 'StrictHostKeyChecking=no' '10.0.0.31'"
and check to make sure that only the key(s) you wanted were added.
 

3.自动化分发公钥（解决密码问题）

#安装sshpass
[root@m01 ~]# yum -y install sshpass
 
#基本使用
#-p指定密码
#需要回车输入密码
[root@m01 ~]# ssh 172.16.1.7 hostname
root@172.16.1.7's password: 
web01
#使用sshpass不需要输入密码
[root@m01 ~]# sshpass -p1 ssh 172.16.1.7 hostname
web01
 
#使用sshpass 与ssh-copy-id分发公钥
[root@m01 ~]# sshpass -p1 ssh-copy-id 172.16.1.7
/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
 
Number of key(s) added: 1
 
Now try logging into the machine, with:   "ssh '172.16.1.7'"
and check to make sure that only the key(s) you wanted were added.
[root@m01 ~]# ssh 172.16.1.7 hostname
web01
 

温馨提示：

sshpass 与 ssh-copy-id 的时候，如果第一次连接的时候，提示yes/no，sshpass就失效了

解决方法：

[root@m01 ~]# sshpass -p1 ssh-copy-id -i ~/.ssh/id_rsa.pub -oStrictHostKeyChecking=no  10.0.0.41
/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
 
Number of key(s) added: 1
 
Now try logging into the machine, with:   "ssh -o 'StrictHostKeyChecking=no' '10.0.0.41'"
and check to make sure that only the key(s) you wanted were added.

补充：

sshpass 适用于ssh相关的命令提供密码：ssh，scp，ssh-copy-id

expect 是一门语言，用于实现非交互式判断，认证相关操作

五、自动化创建与分发脚本

#自动化分发脚本
#!/bin/bash
#author: wh 
#desc: 一键创建秘钥对 分发秘钥对 
 
#1.vars
pass=1
ips="172.16.1.7 172.16.1.31 172.16.1.41 172.16.1.8"
. /etc/init.d/functions
 
#2.创建秘钥对
if [ -f ~/.ssh/id_rsa ] ;then
   echo "已经创建过秘钥对"
else
   echo "正在创建秘钥对...."
   ssh-keygen -t rsa  -f  ~/.ssh/id_rsa   -P ''  &>/dev/null
   if [ $? -eq 0 ];then
       action "密钥创建成功" /bin/true
   else
       action "密钥创建失败" /bin/false
   fi
fi
 
#3.通过循环发送公钥
for ip  in  $ips 
do 
   sshpass -p${pass} ssh-copy-id -i ~/.ssh/id_rsa.pub -oStrictHostKeyChecking=no  $ip &>/dev/null
   if [ $? -eq 0 ];then
       action "$ip 公钥分发 成功" /bin/true
   else
       action "$ip 公钥分发 失败" /bin/false
   fi
done
 
[root@m01 ~]# sh fenfa.sh 
正在创建秘钥对....
密钥创建成功                                               [  OK  ]
172.16.1.7 公钥分发 成功                                   [  OK  ]
172.16.1.31 公钥分发 成功                                  [  OK  ]
172.16.1.41 公钥分发 成功                                  [  OK  ]
172.16.1.8 公钥分发 失败                                   [FAILED]
 
#自动化检查脚本
[root@m01 ~]# cat check.sh 
#!/bin/bash
# author: wh
# desc: 批量在所有机器上执行命令
for   ip  in  172.16.1.7 172.16.1.31 172.16.1.41 172.16.1.8
do
    ssh  $ip   hostname
done
[root@m01 ~]# sh check.sh 
web01
nfs
backup
ssh: connect to host 172.16.1.8 port 22: No route to host