CentOS更改yum源

1.备份现有的源

mv /etc/yum.repos.d /etc/yum.repos.d.backup

2.设置新的yun目录

mkdir /etc/yum.repos.d

3.安装wget

yum install -y wget

4.根据系统版本选择镜像源

##CentOS 5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo

##CentOS 6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

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

CentOS 8
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-8.repo

5.清除文件并重建元数据缓存

yum clean all
yun makecache

6.更新软件包

yum update -y

完成！