YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/repo/arch combination/
removing mirrorlist with no valid mirrors: /var/cache/yum/x86_64/6/base/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: base

http://mirrors.aliyun.com/centos/6/os/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - “The requested URL returned error: 404 Not Found”
Trying other mirror.

打開repo文件：

vim /etc/yum.repos.d/CentOS-Base.repo

[base]
name=CentOS-$releasever
failovermethod=priority
baseurl=https://vault./6.9/os/x86_64/
gpgcheck=0

把repo文件里的東西都刪掉 換上這個就行了