在rhel7上搭建centos7的yum源

1. 再查看现在主机上的yum源，并将它们删除

[root@localhost ~]# rpm -qa|grep yum | xargs rpm -e --nodeps

# --nodeps 不管有没有依赖的包，都将包删除

2. 下载新的yum包

#这里都是拿的是阿里云的yum源，需要先确定是否还存在资源，再进行下载
# PS: 请按顺序下载

wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm

wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-3.4.3-150.el7.centos.noarch.rpm

wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-40.el7.noarch.rpm

wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/yum-utils-1.1.31-40.el7.noarch.rpm

wget https://mirrors.aliyun.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm

 3. 按顺序将下载好的yum源安装

rpm -ivh

4. 更新yum源

# 先备份主机上原先存在的yum源，免得出错
mv /etc/yum.repo.d/rhel-Base.repo ./rhel-Base.repo.bak

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

# 编辑Centos-7.repo ， 将$releasever字样的地方全部替换为7
vi Centos-7.repo
#在vi中命令模式下输入
%s/$releasever/7/g

 5. 运行yum makecache生成缓存

yum clean all
yum makecache
yum update
yum list