备份
[root@iZ2ze1e3u7m7oe426pyndaa ~]# cd /etc/yum.repos.d/
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# ll
total 48
-rw-r--r-- 1 root root 635 Nov 20 2020 CentOS-AppStream.repo
-rw-r--r-- 1 root root 619 Nov 20 2020 CentOS-Base.repo
-rw-r--r-- 1 root root 701 Nov 20 2020 CentOS-centosplus.repo
-rw-r--r-- 1 root root 1329 Nov 20 2020 CentOS-CR.repo
-rw-r--r-- 1 root root 668 Nov 20 2020 CentOS-Debuginfo.repo
-rw-r--r-- 1 root root 227 Nov 20 2020 CentOS-epel.repo
-rw-r--r-- 1 root root 663 Nov 20 2020 CentOS-Extras.repo
-rw-r--r-- 1 root root 242 Nov 20 2020 CentOS-fasttrack.repo
-rw-r--r-- 1 root root 928 Nov 20 2020 CentOS-Media.repo
-rw-r--r-- 1 root root 639 Nov 20 2020 CentOS-PowerTools.repo
-rw-r--r-- 1 root root 1382 Nov 20 2020 CentOS-Sources.repo
-rw-r--r-- 1 root root 74 Nov 20 2020 CentOS-Vault.repo
[[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# mkdir /home/ydt/yum.repos.d.ori
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# cp * /home/ydt/yum.repos.d.ori/
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# ll /home/ydt/yum.repos.d.ori/
total 48
-rw-r--r-- 1 root root 635 Feb 15 14:03 CentOS-AppStream.repo
-rw-r--r-- 1 root root 619 Feb 15 14:03 CentOS-Base.repo
-rw-r--r-- 1 root root 701 Feb 15 14:03 CentOS-centosplus.repo
-rw-r--r-- 1 root root 1329 Feb 15 14:03 CentOS-CR.repo
-rw-r--r-- 1 root root 668 Feb 15 14:03 CentOS-Debuginfo.repo
-rw-r--r-- 1 root root 227 Feb 15 14:03 CentOS-epel.repo
-rw-r--r-- 1 root root 663 Feb 15 14:03 CentOS-Extras.repo
-rw-r--r-- 1 root root 242 Feb 15 14:03 CentOS-fasttrack.repo
-rw-r--r-- 1 root root 928 Feb 15 14:03 CentOS-Media.repo
-rw-r--r-- 1 root root 639 Feb 15 14:03 CentOS-PowerTools.repo
-rw-r--r-- 1 root root 1382 Feb 15 14:03 CentOS-Sources.repo
-rw-r--r-- 1 root root 74 Feb 15 14:03 CentOS-Vault.repo
清空yum源配置文件（注意目录地址）
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# rm -rf *
下载新的阿里云镜像源
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
--2022-02-15 14:04:11-- https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
Resolving mirrors.aliyun.com (mirrors.aliyun.com)... 39.96.118.189, 39.96.118.196, 39.96.118.148, ...
Connecting to mirrors.aliyun.com (mirrors.aliyun.com)|39.96.118.189|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2495 (2.4K) [application/octet-stream]
Saving to: ‘/etc/yum.repos.d/CentOS-Base.repo’
/etc/yum.repos.d/CentOS-Base.repo 100%[================================================================================================================>] 2.44K --.-KB/s in 0s
2022-02-15 14:04:11 (63.2 MB/s) - ‘/etc/yum.repos.d/CentOS-Base.repo’ saved [2495/2495]
生成缓存
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# yum makecache
CentOS-8.5.2111 - Base - mirrors.aliyun.com 25 MB/s | 4.6 MB 00:00
CentOS-8.5.2111 - Extras - mirrors.aliyun.com 296 kB/s | 10 kB 00:00
CentOS-8.5.2111 - AppStream - mirrors.aliyun.com 46 MB/s | 8.4 MB 00:00
Metadata cache created.
[root@iZ2ze1e3u7m7oe426pyndaa yum.repos.d]# ll
total 4
-rw-r--r-- 1 root root 2495 Feb 14 21:16 CentOS-Base.repo