【记录】yum update后yum makecache 源报错：404 not found

急着洗澡睡觉，仓促一记



今天下午yum clean 然后update后，就无法下载缓存包了，运行yum makecache要么提示

http://mirrors.cloud.aliyuncs.com/centos/7-7.1908.0.el7.centos/os/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found
Trying other mirror.

要么提示

https://mirrors.tuna.tsinghua.edu.cn/docker-ce/linux/centos/7-7.1908.0.el7.centos/x86_64/stable/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Foun

这两个一个是阿里源，一个是清华源，ping 了一下域名，都可以ping通，点进去看

而我的版本是 7-7.1908.0.el7.centos
导致在源内找不到我的版本，于是我找到/etc/yum.repos.d/CentOS-Base.repo查看源地址是怎么和版本拼接，发现是通过一个变量$releasever

[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
        http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
...

所以关键就是修改这个变量为源里所有的版本号，我的版本是Centos 7,所以直接改为7即可

echo "7" > /etc/yum/vars/releasever