不知道为啥就开始出现同步仓库缓存失败的问题，无法正常安装一些工具包。错误提示如下：
上报错！！！
然后百思不得其解，我寻思系统默认的yum源可能因为网络的原因连不上也就算了，国内的源不应该啊，是不是配置有问题呢？结果还真是，baseurl中的$releasever和$basearch占位符不知为何无效。故将$releasever改为8，将$basearch改为x86_64后问题解决。修改后的各个配置文件内容如下：
### cat CentOS-Base.repo ### [base] name=CentOS-8 - Base - mirrors.aliyun.com failovermethod=priority baseurl=https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/ http://mirrors.aliyuncs.com/centos/8/BaseOS/x86_64/os/ http://mirrors.cloud.aliyuncs.com/centos/8/BaseOS/x86_64/os/ gpgcheck=1 gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official ### cat CentOS-AppStream.repo ### [AppStream] name=CentOS-8 - AppStream - mirrors.aliyun.com failovermethod=priority baseurl=https://mirrors.aliyun.com/centos/8/AppStream/x86_64/os/ http://mirrors.aliyuncs.com/centos/8/AppStream/x86_64/os/ http://mirrors.cloud.aliyuncs.com/centos/8/AppStream/x86_64/os/ gpgcheck=1 gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official ### cat CentOS-Extras.repo ### [extras] name=CentOS-8 - Extras - mirrors.aliyun.com failovermethod=priority baseurl=https://mirrors.aliyun.com/centos/8/extras/x86_64/os/ http://mirrors.aliyuncs.com/centos/8/extras/x86_64/os/ http://mirrors.cloud.aliyuncs.com/centos/8/extras/x86_64/os/ gpgcheck=1 gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official ### cat CentOS-Epel.repo ### [epel] name=CentOS-$releasever - Epel baseurl=http://mirrors.aliyun.com/epel/8/Everything/$basearch enabled=1 gpgcheck=0 ### cat CentOS-PowerTools.repo ### [PowerTools] name=CentOS-8 - PowerTools - mirrors.aliyun.com failovermethod=priority baseurl=https://mirrors.aliyun.com/centos/8/PowerTools/x86_64/os/ http://mirrors.aliyuncs.com/centos/8/PowerTools/x86_64/os/ http://mirrors.cloud.aliyuncs.com/centos/8/PowerTools/x86_64/os/ gpgcheck=1 enabled=0 gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official ### cat CentOS-centosplus.repo ### [centosplus] name=CentOS-8 - Plus - mirrors.aliyun.com failovermethod=priority baseurl=https://mirrors.aliyun.com/centos/8/centosplus/x86_64/os/ http://mirrors.aliyuncs.com/centos/8/centosplus/x86_64/os/ http://mirrors.cloud.aliyuncs.com/centos/8/centosplus/x86_64/os/ gpgcheck=1 enabled=0 gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
做完以上修改后问题解决，没有再提示同步仓库缓存失败了：
