基本使用https://www.cnblogs.com/kklinux/p/yum.html
1.进入到指定目录,删除其他配置文件
cd /etc/yum.repos.d
rm -rf *.repo
2.配置yum,两种只配一种
########配置本地yum仓库
vim local.repo
[local]
name=local
baseurl=file:///mnt
gpgcheck=0
enabled=1
mount /dev/cdrom /mnt
########配置网络yum仓库阿里云镜像
cat > /etc/yum.repos.d/CentOS.repo <<\EOF
CentOS-Base.repo#
[base]
name=CentOS-releasever−Base−mirrors.aliyun.combaseurl=http://mirrors.aliyun.com/centos/7/os/basearch/
gpgcheck=0
[updates]
name=CentOS-releasever−Updates−mirrors.aliyun.combaseurl=http://mirrors.aliyun.com/centos/7/updates/basearch/
gpgcheck=0
[extras]
name=CentOS-releasever−Extras−mirrors.aliyun.combaseurl=http://mirrors.aliyun.com/centos/7/extras/basearch/
gpgcheck=0
epel.repo#
[epel]
name=Extra Packages for Enterprise Linux 7 - basearchbaseurl=http://mirrors.aliyun.com/epel/7/basearch
gpgcheck=0
EOF
3.使yum生效
yum clean all # 清除系统所有的yum缓存
yum makeacache # 生成新的yum缓存
yum repolist #列出yum所有仓库
########配置网络yum仓库2,中国科学技术大学、中国科学技术大学网络信息中心支持
1.配置/etc/yum.repos.d/CentOS-Base.repo
cat > /etc/yum.repos.d/CentOS-Base.repo <<\EOF
[base]
name=CentOS-releasever−Basebaseurl=http://mirrors.cernet.edu.cn/centos/releasever/os/$basearch/
gpgcheck=0
[updates]
name=CentOS-releasever−Updatesbaseurl=http://mirrors.cernet.edu.cn/centos/releasever/updates/$basearch/
gpgcheck=0
[extras]
name=CentOS-releasever−Extrasbaseurl=http://mirrors.cernet.edu.cn/centos/releasever/extras/$basearch/
gpgcheck=0
EOF
2.配置/etc/yum.repos.d/epel.repo
cat > /etc/yum.repos.d/epel.repo <<\EOF
[epel]
name=Extra Packages for Enterprise Linux 7 - basearchbaseurl=http://mirrors.cernet.edu.cn/epel/7/basearch
gpgcheck=0
EOF
3.将releasever变量改为操作系统版本
sed -i 's/\releasever/7/’ CentOS-Base.repo
