这里还涉及到一个ssh的免密传输文件，需要进行配置才行。
注意：公钥相当于锁，私钥相当于钥匙，客户端创建一对钥匙和锁，要想做到SSH免密登录，就要将锁分发到服务器并装锁，然后客户端就可以利用这个钥匙开锁
建立SSH信任关系：
- 生成秘钥（公钥和私钥）
# 切换到ssh目录
[root@rhel8 ~]# cd /root/.ssh/
[root@rhel8 .ssh]# ls
known_hosts
# 生成秘钥文件（一路回车即可）
[root@rhel8 .ssh]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
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:
SHA256:1eFqA0YG8GwTX/U+lGikRGWl+Zi7C/bEhpm4xJzxi5A root@rhel8.tourby.cn
The key‘s randomart image is:
+---[RSA 3072]----+
| ..o.o.+o*.. |
| o = o * * . |
| = + o B + |
| . o o o * |
| S + o + |
| + * * . . |
| E * B = |
| o + * . |
| o . +. |
+----[SHA256]-----+
- 将公钥拷贝到其他服务器上
[root@rhel8 .ssh]# ls
id_rsa id_rsa.pub known_hosts
# 这种方式会覆盖拷贝过去的服务器上的authorized_keys文件
[root@rhel8 .ssh]# scp -r id_rsa.pub root@IP地址:/root/.ssh/authorized_keys
# 这种不会覆盖，会追加。回车后输入密码即可
[root@rhel8 .ssh]# ssh-copy-id -i /root/.ssh/id_rsa.pub ip地址
脚本内容：
[root@rhel8 shell]# vim auto_scp.sh
#!/bin/bash
# auto scp files for client
# by authors tanbaobao 2020/06/09
FILES=$*
if [ -z $* ];then
echo -e ‘\033[32mUsage: {$0 /boot|/tmp|file.txt}\033[0m‘
exit
fi
for i in `echo IP地址1 IP地址2 ...`
do
scp -r $FILES root@$i:/root/
done