清除旧 yum 版本
rpm -qa|grep yum
rpm -qa|grep yum|xargs rpm -e --nodeps
下载并安装新 yum 安装包
# 下载
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-168.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-rhn-plugin-2.0.1-10.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-utils-1.1.31-54.el7_8.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-54.el7_8.noarch.rpm
# 安装
rpm -ivh *.rpm
配置 yum 源
vim /etc/yum.repos.d/Centos7-Base.repo
[base]
name=CentOS-7 - Base
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=$basearch&repo=os
baseurl=http://mirrors.tuna.tsinghua.edu.cn/centos/7/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.tuna.tsinghua.edu.cn/centos/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-7 - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=$basearch&repo=updates
baseurl=http://mirrors.tuna.tsinghua.edu.cn/centos/7/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.tuna.tsinghua.edu.cn/centos/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras]
name=CentOS-7 - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=7&arch=$basearch&repo=extras
baseurl=http://mirrors.tuna.tsinghua.edu.cn/centos/7/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.tuna.tsinghua.edu.cn/centos/RPM-GPG-KEY-CentOS-7
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-7 - Plus
baseurl=http://mirrors.tuna.tsinghua.edu.cn/centos/7/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.tuna.tsinghua.edu.cn/centos/RPM-GPG-KEY-CentOS-7
清除 yum 缓存
yum clean all
yum makecache