from：https://mirror.tuna.tsinghua.edu.cn/help/centos/
清华CentOS 镜像使用帮助
建议先备份 CentOS-Base.repo
sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
然后编辑 /etc/yum.repos.d/CentOS-Base.repo 文件，在 mirrorlist= 开头行前面加 # 注释掉；并将 baseurl= 开头行取消注释（如果被注释的话），把该行内的域名（例如mirror.centos.org）替换为 mirrors.tuna.tsinghua.edu.cn。
或者，你也可以直接使用如下内容覆盖掉 /etc/yum.repos.d/CentOS-Base.repo 文件：（未经充分测试）
CentOS 7版本:
# CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [base] name=CentOS-$releasever - Base baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/os/$basearch/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7 #released updates [updates] name=CentOS-$releasever - Updates baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/updates/$basearch/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/extras/$basearch/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/centosplus/$basearch/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7
CentOS 8版本：
# CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [BaseOS] name=CentOS-$releasever - Base baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/BaseOS/$basearch/os/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=BaseOS&infra=$infra enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial [AppStream] name=CentOS-$releasever - AppStream baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/AppStream/$basearch/os/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial [PowerTools] name=CentOS-$releasever - PowerTools baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/PowerTools/$basearch/os/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=PowerTools&infra=$infra enabled=0 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial #additional packages that may be useful [extras] name=CentOS-$releasever - Extras baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/extras/$basearch/os/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras enabled=1 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/centosplus/$basearch/os/ #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
最后，更新软件包缓存
sudo yum makecache -y