将centos7镜像源更新为阿里镜像源

1.被分享centos7自带的镜像源

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

2.下载CentOS 7的repo文件

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

3.更新镜像源

　　重新生成缓存

yum clean all
yum makecache

4.将文件中的所有http开头的地址更改为https

vim /etc/yum.repos.d

5.更新yum

yum update