简介

现在很多场景都会用到rsync去备份文件，默认情况下，执行rsync命令是需要输入密码的，如果写shell脚本，就不太方便，所以这里就配置免密。

环境简介

操作系统版本：CentOS Linux release 7.7.1908 (Core)
主机A：192.168.17.128
主机B：192.168.17.130

在本地服务器生成公钥

在Linux操作系统，要是实现2台主机之间实现免密登录，需要先在本地Linux服务器生成一个公钥，然后将公钥拷贝到远程服务器上，就可以实现远程免密登录了。

1.在192.168.17.128服务器上生成公钥
执行ssh-keygen命令之后，需要输入的选项，可以直接回车

[mysql@192 ~]$ ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/home/mysql/.ssh/id_rsa): 
Created directory '/home/mysql/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/mysql/.ssh/id_rsa.
Your public key has been saved in /home/mysql/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:+Ay6O18jexPaARVpDlTZkbz26U9fpDSmSzGjI+YpGu4 mysql@192.168.17.128
The key's randomart image is:
+---[RSA 2048]----+
|     ...o*.o     |
|      . = +      |
|       =   .     |
|      ... o      |
|      o.S. .+.+ .|
|     . +o  .oB + |
|    o .oBoo.o o .|
|   ..oo*++ o.o ..|
|   .E=ooo.  ... .|
+----[SHA256]-----+

上面命令执行完毕之后，会在mysql用户目录下，生成一个目录“.ssh”

[mysql@192 ~]$ ls -al|grep -i ssh
drwx------   2 mysql mysql      38 Sep  5 10:50 .ssh

在.ssh目录下会有2个文件，一个是公钥，一个是私钥

[mysql@192 .ssh]$ ll
total 8
-rw------- 1 mysql mysql 1675 Sep  5 10:50 id_rsa
-rw-r--r-- 1 mysql mysql  402 Sep  5 10:50 id_rsa.pub

上传公钥到远程服务器

现在将192.168.17.128服务器上生成的公钥，上传到192.168.17.130服务器上。

1.执行ssh-copy-id 命令拷贝公钥到远程服务器

[mysql@192 ~]$ ssh-copy-id -i /home/mysql/.ssh/id_rsa.pub mysql@192.168.17.130
/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/mysql/.ssh/id_rsa.pub"
The authenticity of host '192.168.17.130 (192.168.17.130)' can't be established.
ECDSA key fingerprint is SHA256:I5mQVkAiPi20DGxpgdJHHiI+BoboH78H5hvxweJdxAc.
ECDSA key fingerprint is MD5:1c:6f:ad:b2:20:9d:5f:0e:7f:96:73:17:30:b1:55:1f.
Are you sure you want to continue connecting (yes/no)? yes
/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
mysql@192.168.17.130's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'mysql@192.168.17.130'"
and check to make sure that only the key(s) you wanted were added.

2.检查远程服务器认证key
检查192.168.17.130服务器用户mysql目录.ssh有认证key

[mysql@oracle11gR2 .ssh]$ pwd
/home/mysql/.ssh
[mysql@oracle11gR2 .ssh]$ ls -l
total 4
-rw-------. 1 mysql mysql 402 Jan  4 05:42 authorized_keys

3.测试远程免密登录

[mysql@192 ~]$ ssh mysql@192.168.17.130
Last login: Mon Jan  4 05:41:57 2021
[mysql@oracle11gR2 ~]$ 

可以看到已经可以远程免密登录了。

rsync免密传输

上面配置好mysql免密ssh登录之后，就可以rsync免密传输了。

[mysql@192 testdir]$ rsync -avP /home/mysql/testdir/*log mysql@192.168.17.130:/home/mysql/testlog
sending incremental file list
test.log
             10 100%    0.00kB/s    0:00:00 (xfr#1, to-chk=0/1)

sent 117 bytes  received 35 bytes  304.00 bytes/sec
total size is 10  speedup is 0.07

可以看到已经不需要输入密码了。