In the test server for docker learning, some centos7 software installation and their own server is not compatible so lead to yun download software when the error: Error: xz compression not available

For the error solution.
rm -fr /var/cache/yum/x86_64/6/epel/
rm -rf /etc/yum.repos.d/epel*


Reinstall epel and base

wget -O/etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repohttp://mirrors.aliyun.com/repo/epel-7.repo
yum repolist