[系统运维]Centos7更换yum源

1.下载wget工具：
[root@localhost ~]# yum install -y wget

2. yum源保存目录： /etc/yum.repos.d/

3.备份yum源，更改为CentOS-Base.repo.backup

[root@localhost ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

4.下载yum源到/etc/yum.repos.d/目录：

#163源

[root@localhost ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo

#阿里源

[root@localhost ~]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

4.清理缓存
[root@localhost ~]# yum clean all

5.生成新的缓存
[root@localhost ~]# yum makecache