redhat7安装yum，配置清华yum源

卸载已经安装的yum

rpm -qa|grep yum|xargs rpm -e --nodeps

创建一个文件夹用来存放下载的yum安装包

mkdir /tmp/yum
cd /tmp/yum

下载yum安装包

wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-163.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-52.el7.noarch.rpm 
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm 
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-cron-3.4.3-163.el7.centos.noarch.rpm  

安装yum(忽略依赖强制安装)

有可能会遇到依赖rpm的情况所以忽略依赖强制安装

rpm -ivh * --force --nodeps

配置yum源

cd /etc/yum.repos.d/
mv redhat.repo redhat.repo.bak

清华的镜像

https://mirror.tuna.tsinghua.edu.cn/help/centos/

记得将
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-7
替换为
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
还有
$releasever
替换为
7

更新key

mkdir /etc/pki/rpm-gpg
cd /etc/pki/rpm-gpg
wget https://mirrors.tuna.tsinghua.edu.cn/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7

更新软件包缓存，并更新

yum makecache
yum update
yum upgrade