CentOS6官方不维护了，更新怎么办？

#备份CentOS-Base.repo
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak

#修改yum源
#CentOS6为：
wget -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

#Centos7为：
wget -o /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

#备份配置文件
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak2

#修改配置
vim /etc/yum.repos.d/CentOS-Base.repo

[centos-office]
name=centos-office
failovermethod=priority
baseurl=https://vault.centos.org/6.10/os/x86_64/
gpgcheck=1
gpgkey=https://vault.centos.org/6.10/os/x86_64/RPM-GPG-KEY-CentOS-6

#清空yum缓存
yum clean all

#重建yum缓存
yum makecache

#列出yum列表
yum list