错误：Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again

通过yum -y install XXX 尝试安装软件，出现Cannot retrieve repository metadata (repomd.xml) for repository: base. Please verify its path and try again的错误

问题原因：对应的镜像库中无法找到对应的repomd.xml文件

问题解决：原centos/6/ 下已经没有相关的文件，尝试修改本地镜像配置文件
步骤：

cd /etc/yum.repos.d

vim CentOS-Base.repo

因为$releasever 获取的是centos的版本号，我的centos获取的版本为6，但是镜像站中无对应版本文件，因此需要修改本地配置文件

:%s/$releasever/7/g #将文件中$releasever全部改成7或其他版本

或者替换参考的配置

        http://mirrors.cloud.aliyuncs.com/centos/7/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#released updates 
[updates]
name=CentOS-7 - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/7/updates/$basearch/
        http://mirrors.aliyuncs.com/centos/7/updates/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/7/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-7 - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/7/extras/$basearch/
        http://mirrors.aliyuncs.com/centos/7/extras/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/7/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-7 - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/7/centosplus/$basearch/
        http://mirrors.aliyuncs.com/centos/7/centosplus/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/7/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7

#contrib - packages by Centos Users
[contrib]
name=CentOS-7 - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/7/contrib/$basearch/
        http://mirrors.aliyuncs.com/centos/7/contrib/$basearch/
        http://mirrors.cloud.aliyuncs.com/centos/7/contrib/$basearch/

退出保存

:wq

清除和重新生成缓存

yum clean all 
yum makecache 

完成之后再次通过yum -y install XXX 尝试安装软件