centos6 yum源不可用问题解决

因为centos6各大开源镜像站已经停止维护了，只有阿里的还可以。

在centos命令行界面下执行一下几条命令

sed -i "s|enabled=1|enabled=0|g" /etc/yum/pluginconf.d/fastestmirror.conf
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
curl -o /etc/yum.repos.d/CentOS-Base.repo https://www.xmpan.com/Centos-6-Vault-Aliyun.repo
yum clean all
yum makecache