Centos7更改yum源與更新系統

1.首先備份yum

/ect/yum.repos.d/CentOS-Base.repo

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

2.替換yum源

替換爲阿里源

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

3.生成緩存

yum makecache

4.更新系統

yum -y update